1 3/4 cups roasted, unsalted macadamia nuts
3 tablespoons all-purpose flour
Finely grated zest of 1 orange (about 2 tablespoons)
1/4 teaspoon fine salt
3/4 cup sugar
2 tablespoons heavy cream
2 tablespoons light corn syrup
5 tablespoons unsalted butter
1/2 teaspoon pure vanilla extract
6 ounces semisweet chocolate chips
Preheat to 350F. Line a baking sheet with a silicone baking mat or parchment paper.
Pulse the macadamia nuts in a food processor until finely chopped, but not pasty. Stir together the nuts, flour, zest and salt in a large bowl.
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 nut mixture and stir just to combine. Set aside until cool enough to handle, 30 minutes.
Scoop rounded teaspoons of batter and roll into balls. Place on prepared baking sheet, leaving about 3 to 4 inches between each cookie since they spread.
Bake 1 pan at a time, until the cookies are thin and an even golden brown color throughout, about 10 to 11 minutes. Cool on baking sheet for 5 minutes, then transfer to racks to cool. Repeat with remaining batter.
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. Drizzle melted chocolate over Florentines as desired. Set aside at room temperature until chocolate is set.