Step 1

Position a rack in the center of the oven and preheat to 350 degrees F. Line a baking sheet with a silicone baking mat or parchment paper.

Step 2

Pulse the almonds in a food processor until finely chopped, but not pasty. Stir together the nuts, flour, zest and salt in a large bowl.

Step 3

Put the sugar, cream, corn syrup and butter in a small saucepan. Cook over medium heat, stirring occasionally, until mixture comes to a rolling boil and sugar is completely dissolved. Continue to boil for 1 minute. Remove from heat and stir in the vanilla, then pour mixture into almond mixture and stir just to combine. Set aside until cool enough to handle, 30 minutes.

Step 4

Scoop rounded teaspoons (for 3-inch cookies) or rounded tablespoons (for 6-inch cookies) of batter and roll into balls. Place on prepared baking sheet, leaving about 3 to 4 inches between each cookie since they spread.

Step 5

Bake 1 pan at a time, until the cookies are thin and an even golden brown color throughout, rotating pans halfway through baking time, about 10 to 11 minutes. Cool on baking sheet for 5 minutes, then transfer to racks to cool. Repeat with remaining batter. Serve.

Step 6

Optional chocolate topping: Put the chocolate in a medium heatproof bowl. Bring a saucepan filled with 1 inch or so of water to a very low simmer; set the bowl over, but not touching, the water. Stir the chocolate occasionally until melted and smooth. (Alternatively, put the chocolate in a medium microwave-safe bowl. Melt at 50 percent power in the microwave until soft, about 1 minute. Stir, and continue heat until completely melted, about 1 to 2 minutes more.)

Step 7

For sandwiches: Drop about 1/2 teaspoon chocolate onto on the flat side of half of the cookies and press together with remaining halves. Return to rack and let chocolate set.

Step 8

For chocolate decor: Drizzle melted chocolate over Florentines as desired. Set aside at room temperature until chocolate is set.