Sweet friends, I am posting a recipe that I think many of you will not make. Keep in mind this is a legacy blog and, in part, I am recording family favourites. For years, this appeared every Xmas, made by my mother-in-law. Once she stopped baking, it was missed, so I made it my business to figure it out. Maybe one day someone else in the family will join me in carrying on the tradition.
There’s quite a story about this 125 year old confection, but I won’t add it here. Google it or visit this site. If you have ever been to Budapest, you undoubtedly went to the famous Cafe Gerbeaud. This is one of their signature desserts. Zserbo, Gerbaud. It goes by two spellings - but each is pronounced the same way. (“G” as in Jerry, “bow” as in “bowl” - Jer-bow.)
The recipe is a wee bit complex - and you know me - I can even make a simple recipe seem complex by the time I outline techniques and tips - haha. I write these with love and the goal of making your experience foolproof.
This combines tweaks from several recipes and experimentation, but is mainly based on a 2002 Corvina Hungarian recipe book, called “Hagyomanyos Magyar Sutemenyek”, so all the measures are by weight. Many measures in the book specify “dkg” - the abbreviation for dekagram / decagram. That used to puzzle me until I realized that I simply have to multiply by 10 to get the gram measure - and my kitchen scale can measure that! (e.g. 15 dkg = 150 g) A kitchen scale is a great investment!
Pondering - I’ve made this 4-5 times and still wonder if I should maybe use more apricot jam… yes, I have added a bit more.
Things you’ll need in addition to ingredients:
a digital scale - since this comes from a European recipe, many ingredients are by weight, and… equally dividing the dough and fillings is easier by weight.
digital thermometer - to measure milk temp for activating yeast
11 x 7 baking pan with high sides
parchment paper
must admit you’ll be using a lot of dishes by the time you divide the jam and walnuts into three equal portions.
Prep Ahead
Like many semi-complex baking projects, things go better when you have prepped ahead - there is much here that can - and SHOULD - be done the day before - makes baking day so much easier. Definitely grind the walnuts ahead of time.
Create a parchment template for rolling out the dough to fit the pan
Butter the end/sides of the baking pan and line it with a parchment sling
grind the walnuts - they will be mixed with the superfine sugar and lemon zest but here’s a tip. The lemon zest is better dispersed if you rub it into the sugar with your fingers. Add this to the walnuts and cover tightly until baking day.
If you cannot purchase thick apricot filling, buy regular jam and cook it down; divide into 3 equal portions ahead of time or on baking day
measure and cut the butter into chunks and store in the refrigerator until needed
Work Flow
BEST when made ahead! Most recipes agree that this is best 3 or more days after it’s made. It’s edible when freshly baked, but it’s sort of dry and all the bits have not “gelled” together. Sitting, covered, in the fridge or a cool place gives the jam time to soak into the cake layers - which begin to stick together instead of falling apart.
Big picture - you’ll be making a yeast dough requiring a quick proof at the start; then layering 4 pieces of dough with jam and walnut filling; once prepped, it is proofed again at room temperature for 30 minutes before being baked; a chocolate glaze is added after.
Preheat your oven to 350 F.
Take 3 eggs out of the fridge (you’ll be separating them and using only the yolks); butter should also be prepped though it does not have to be room temp soft.
Prepare 300 g (or a bit more) thick apricot filling and divide it into 3 equal portions (can be done ahead). (It’s better to have too much apricot filling on hand vs not enough.) If you do not have a thick apricot spread you may have to cook down some regular apricot jam. (See Notes below.)
Prepare walnuts and divide into 3 equal portions (can be done ahead).
Prepare the baking pan by buttering it, then make a parchment sling (see photo) - this will make it easier to remove the cake for slicing at the end. Frankly, if you don’t use a parchment sling, you won’t be able to remove the cake for precise, pretty slicing. (Can be done ahead.)
Have every single thing prepped and measured out before you begin - that will make the process feel like a breeze.
Make the dough.
Proof it in the fridge for 10-15 minutes
Assemble the layers (dock with fork, spread with jam, sprinkle with walnuts - repeat three times and place the last piece of dough on top- and dock that too.) For ease of handling, refrigerate each layer for 10 minutes - makes it easier to drop the thin layer of pastry into place.
Proof at room temperature for 30 minutes.
Bake at 350 F for 25-30 minutes.
Cool and cover with chocolate glaze.
Cover and store in a cool place for a few days to let it all come together nicely.
Walnut Filling
150 g ground walnuts
150 g superfine sugar
1 tsp lemon zest
Combine walnuts, sugar and lemon zest. For best distribution throughout walnuts, rub lemon zest into the sugar and then combine both with the walnuts. Divide this mixture into 3 equal portions of about 100 g each.
See Notes below re how to grind the walnuts. Obviously, they must be fresh and not rancid. Most importantly, do not toast the walnuts before grinding them. So many North American recipes suggest toasting nuts, but in this case, toasting tends to dry out the nuts and you want them to be natural and moist.
Apricot Jam Filling
300 g (or 350g) of apricot jam
1/2 tsp rum flavouring (optional)
See Notes (below) about the jam needing to be a bit thicker than jam right out of the jar. Mix the jam with the rum flavouring - see Notes about rum flavouring options. You may need to warm this mixture a tiny bit (15 seconds) to make it easier to mix in the rum flavouring and for spreading. Using an offset knife, you’ll be spreading one of the three equal portions onto a layer of dough. Update - when/if the apricot spread seemed to be not quite enough I simply supplemented it with a bit of regular apricot jam.
Vintage walnut grinder
Thick apricot paste / jam
Parchment sling in baking dish
Parchment template for dough
The Dough
16-20 g quick rise yeast (see Notes)
100 ml milk
1 tsp sugar (regular or superfine)
The yeast is going to bubble up, so use a 2-cup measuring cup. To properly activate yeast, the liquid must be 100-110 F. If the liquid (milk) is too hot it will kill the yeast, too cool and it won’t activate. Yeast that is old also will not activate so check the date on the package.
Warm the milk in a microwave to a temperature higher than 110 F (about 30 seconds). Add the sugar and stir to dissolve. Keep checking the temperature and stir in the yeast when the temp is correct (Some sources say the milk should be between 100-110 F, but my yeast package says 120-130 F). If the yeast is alive it will bubble up in 10 minutes.
During this 10 minutes do the next step in your food processor.
350 g flour
pinch of salt
1/4 tsp baking powder
150 g / about 10 TB unsalted butter (84% fat content)
120 g superfine sugar
3 egg yolks
(yeast/milk mixture)
The butter does not have to be super soft, but best if it’s not just out of the fridge. Cut the butter into small pieces. Add the flour, salt and baking powder to your food processor. Pulse 2-3 times to mix these. Drop the butter bits over top. Pulse about 10-12 times to incorporate the butter into a crumbly mixture. Add the sugar and pulse 3-5 times.
Beat the egg yolks by hand and then add the egg yolks and the yeast/milk mixture (from above - once the 10 minutes has elapsed) into the food processor and pulse, then process until the dough comes together. This shouldn't take long.
Transfer the dough to a bowl, cover loosely with plastic wrap and proof in the fridge for 10-15 minutes.
Preheat your oven to 350 F. Divide the dough into 4 pieces. You can weigh each to ensure they are all roughly the same size - in fact the chunk that will be used at the end for the top could weigh slightly more so that it will be a wee bit thicker. (Oddly, the weight can vary slightly each time I make this. Each chunk will probably weigh 190-195 g.) You’ll be rolling / finger-pressing each of these into a rectangular shape to fit into the baking pan. It’s helpful to have a template drawn on a piece of parchment to help with that.
You’ll be layering the dough in the baking pan between fillings. BEST to have the fillings all ready and portioned out equally. IMPORTANT - dock each layer of dough with a fork before covering it with jam and walnuts.
So you are all set, assembly line style. Prep the first chunk of dough which will be the bottom. Tip: Unlike pastry dough, dropping this into the pan may seem challenging. Here’s what I do. I centre the dough on the parchment template, pressing it out a bit. Then I cover that with wax paper - this makes it easier to use a rolling pin to finish spreading out the dough. I put that - parchment, dough and wax paper into the fridge for 3-5 minutes. I remove it from the fridge and place it on my workstation parchment side up. The parchment is stiffer than the wax paper and it’s easier to separate that from the dough first. Then I can pick up the dough and wax paper and use the wax paper to help me position and drop the dough into place. The wax paper is easy to remove - but do this slowly to prevent tearing the dough. DO THIS!
So… once that bottom layer is in the pan, roll out the next layer and put it in the fridge to cool while you cover the first layer with the fillings - this saves time.
Follow this pattern: dough, dock with fork, spread with jam, sprinkle with walnuts - repeat three times and place the last piece of dough on top - and dock that too. If the top layer is not perfectly smooth - no worries - this will be hidden by the glaze.
Tip: the layers stick together better if you do the following - after sprinkling the walnuts over the jam, lightly run a fork through the walnuts to make some of the jam come through. The next layer of dough will stick more easily when a bit of jam comes through versus trying to stick to a dry layer of walnuts.
Cover the baking pan with a cloth or plastic wrap and proof at room temperature for 30 minutes.
Bake at 350 F until the top is lightly golden. Check it at 20 minutes. Don’t bake more than 25 or 30. That top layer is going to be covered with a chocolate glaze so we just want it to be baked, not looking pretty. Let this cool to room temperature in the pan and then cover with chocolate glaze.
Chocolate Glaze
4 oz (114 g) high quality bittersweet 60% chocolate, chips or finely chopped
3/4 cup heavy cream
1 TB corn syrup
I have no idea of the physics here, but measure each of these ingredients perfectly. I have found that if even one measure is off the consistency of the glaze changes. Place 3 oz of the chocolate into a heatproof bowl. Heat the cream and corn syrup in a small saucepan over medium heat until just simmering. Pour this over the chocolate and let it stand about 30 seconds, then stir to combine and then stir in the remaining 1 ounce of chocolate - this helps to temper the chocolate. Let cool until it reaches a nice spreading consistency. If it doesn’t do that at room temperature, put it in the fridge for some minutes - NOT too long otherwise it will become too hard for spreading. Spread it to the edges of the cooled cake using an off-set spatula.
While you can eat this the same day, it will be a bit dry and not authentic. Instead, cover and store it in a cool place for a few days to let it all come together. TIP: It must be absolutely cooled down before covering it with plastic wrap. If not, condensation may form on the plastic and drip onto the chocolate. If that happens you can use a kitchen torch to warm the chocolate and an offset knife to smooth it out again. In 2-3 days, the cake layers will absorb the jam and flavours etc. When ready to serve, lift it out of the pan with the parchment sling. Place it on a cutting board and cut it into diamond shapes. I like to portion them more on the small side than too big. They store very well for days in a covered container in a cool place.
Notes and Tips...
Baking Pan Size - the recipe suggests an 11 x 7 inch pan (with high sides). Did you know that pan sizes are measured across the top, not the bottom, from inside edge to inside edge? Shockingly I do not have a 11 x 7 baking pan. I once unthinkingly made this in my glass baking dish that measures about 13 x 8 - that didn’t work. My other glass baking dish is 10 x 6 - too small. It is possible to buy an 11 x 7 pan, but until I get around to it, I use a dish intended more for casseroles that fits the requirements. Last year that pan broke. I’m taking care that the pan I use instead has high sides - low sides can be problematic.
Ground Walnuts - for European baking, nothing beats walnuts that are ground by hand - they are so light and fluffy. If you don’t have access to a new or vintage grinder, then use a food processor but take care to not turn the nuts into nut butter - use gentle pulses. P.S. Do NOT toast the walnuts before grinding.
Apricot Jam - generally speaking, jam right from the jar is not thick enough for these kinds of European recipes - and many recipes do use apricot jam! I am fortunate because my German deli sells thick apricot spread for precisely this use. If you can’t find that then start by buying good quality apricot jam. (I like Menz & Gasser Prima Frutta. Hero and Bon Maman are also good. (In 2019 I cooked down two 370 g jars of Bon Maman and had enough with some left over. This is a “Goldilocks exercise - not too watery, not too thick - the jam does have to be a bit liquid-y so that it soaks into the pastry in the days after you have baked it.) The jam will likely contain some large chunks of apricot - better to chop those bits, or whiz it briefly in a food processor or with a blender stick. It’s better to have too much jam to work with (and leftovers) than not enough. This cake will be horribly dry if you do not use enough jam.
Rum Flavouring - this is probably not authentic. None of the recipes I have found mention it, but our family taste memory says there was a bit of a rum flavour. You can omit this, or add it in the form of real (sweet) rum, or rum extract, or - my preference - Dr. Oetker Rum Extract - use one of the little vials which is 2 ml = 1/2 tsp.
Quick Rise Yeast - these come in packages of 8 g each. You can open a third package to get 20 g - but I just go with 16 g from the two packages. Seems to work fine. See Fleischmann’s Yeast Basics.
84% Butter - if possible use high fat butter. See my Butter Notes.
Kneading the dough? - just an FYI that some recipes suggested kneading the dough and others said to pull the dough together quickly with minimal handling… well you can see I went with the minimal idea. If you wanted to knead it, transfer it from the food processor to a stand mixer with a dough hook.
Chocolate Glaze - I have tried several glazes from various sources, including overseas family. They have all disappointed. They have not spread well or not cut nicely or become dull after the first day. The winning recipe I use is from Martha Stewart - her Opera Cake Glaze.
For KB Recipe Attribution Practices please click here.
<== CLICK HERE to leave Questions, Comments or Likes! LOVE to hear from you!
You can personalize how this page PRINTS by copying and pasting the page URL into Print Friendly!