Recipe appeared in The Toronto Star, tested by Susan Sampson, adapted from Heirloom Baking With the Brass Sisters by Marilynn and Sheila Brass. 

These are mixed by hand and come together astonishingly quickly. Have everything measured and ready. Line baking sheets with parchment. Bake in preheated 350 F oven. Makes about 36. Store in a tin, with layers separated by waxed paper.

I have made these countless times, though more often as a dessert plating enhancement - never just as a cookie treat. For example, it can dress up a simple Affogato (ice cream with espresso coffee poured over top). As a cookie, they satisfy a craving for chocolate and for crunch at the same time.

Update: Since i do tend to make these only as a plating enhancement - 36 is too many so I have included below, measures for half the recipe. I cannot stress enough to scoop small dollops onto the bake sheets. one teaspoonful can spread to 3-4", and for a plating enhancement, you may want something smaller. You can also roll these into tubes after they are removed form the oven Wait a few minutes until they are cool enough to handle, but still soft.

Use 2 spoons to scoop and dollop. Drop teaspoons** of mixture onto prepared baking sheet at least 3 inches apart. (** smaller than a teaspoon works better - maybe 1/2 tsp). Allow a maximum of 6 cookies per sheet - these are going to spread!! Bake one batch at a time in centre of preheated 350 F oven. Bake until top bubbles and lacy holes develop, 8 to 10 minutes. Remove from oven. Cool 2 to 3 minutes or until firm enough to transfer to rack. Cool completely. Repeat with remaining mixture.

Notes and Tips...

• Chocolate - source specified use baking chocolate, not chocolate chips.
• Bake - the trick to the timing is to watch for the bubbles. Ideal if oven door has a window - turn on oven light and pull cookies when they are bubbling. As they cool, the bubbles "burst" leaving little holes that create the lacy effect. If left in the oven too long / longer the cooled cookies resemble a "brittle"-like hard cookie - which may or may not be desired.
• Separate - even if there are only 6 cookies per bake sheet, they may run together - nudge them apart while still warm and pliable - don't try to move the cookies, just create a little space between them. Similarly, good moment to split a round into a half moon shape - just make a little channel down the middle.
• Shape cookies - there's a moment after they come out of the oven where cookies hold together enough to be lifted from the cookie sheet with a flat spatula, but are still soft enough to form into shapes - cups, etc. This website offers a recipe for Florentines which can similarly be shaped - scroll down to see photos. For even more ideas on shaping - Google 'shaping florentine cookies', and view Image results.