Florentine Cookies

Instructions

1. Preheat the oven to 350°F (175°C) and set a rack in the middle position. Line a baking sheet with parchment paper.
2. Place the almonds in the bowl of a food processor fitted with the metal blade and pulse until finely chopped and crumblike. You want a texture somewhere between almond flour and finely chopped nuts—don’t let it turn pasty.
3. In a medium saucepan, combine the butter, brown sugar, corn syrup, and salt. Set over medium heat and bring to a boil, stirring occasionally, until the sugar is dissolved. Whisk in the vanilla and flour until smooth, then stir in the chopped almonds with a spatula. Remove from the heat and let sit for 20 to 30 minutes to cool and thicken slightly.
4. Drop 1½-teaspoon spoonfuls of batter onto the prepared baking sheet, spacing them about 3 in (8 cm) apart (you should fit 8 per sheet). These look like tiny mounds, but don’t be tempted to make them bigger—they spread a lot. Use your fingers to shape the edges into neat rounds.
5. Bake for 8 to 11 minutes, until evenly golden with a rich butterscotch color—don’t let them get too dark. Slide the parchment off the baking sheet and onto the counter to cool. Once the cookies are crisp, about 5 minutes, gently peel them off the parchment and set on a rack to cool. Repeat with remaining batter.
6. For the filling, place both chocolates in a small microwave-safe bowl. Microwave in 20-second intervals, stirring in between, until about 75% melted. Stir until completely smooth (the residual heat will finish the job—don’t overheat or the chocolate may scorch).
7. Once the cookies have cooled completely, hold one cookie in your hand and spread a thin layer of melted chocolate over the flat side. (The chocolate may poke through the holes—that’s totally fine.) Top with another cookie, flat-side down, and press gently to sandwich. Do your best to match the cookies in size and shape, but don’t make yourself crazy over it; it won’t matter much in the end. Repeat with the remaining cookies.
8. Let sit until the chocolate is set, about 30 minutes. The texture is best after a few hours—or even the next day—when the cookies soften slightly to that perfect crispy-but-not-brittle stage.