1 stick plus 1 tablespoon butter unsalted softened
1 cup cake flour
1 level tablespoon cocoa powder
1 cup confectioners' sugar
0.8 cup hazelnuts toasted
0.3 teaspoon lemon zest finely grated
0.1 teaspoon salt
Equipment
bowl
baking sheet
baking paper
oven
microwave
spatula
Directions
Preheat oven to 350 degrees F. Line 2 baking sheets with parchment paper.
Grind the nuts with confectioners' sugar until powdery (do not make into a paste).
Blend together the butter, lemon zest, salt, and nut mixture in a large bowl with a spatula or spoon until creamy.
Add the flour and cocoa powder, stirring until incorporated. Do not overwork the dough.
Roll level 1/2 teaspoons of dough into tiny balls and arrange 1-inch apart on the prepared baking sheets.
Bake 1 sheet at a time until lightly crisped, about 12 minutes. Slide the parchment paper with the baked cookies onto a rack to cool.
In a microwave-safe bowl, melt the chocolate in the microwave.
Spoon a mound, about 1/8 teaspoon, of melted chocolate onto the flat side of a cookie then top with the flat side of another cookie to make a "sandwich." Repeat.
Plain cookies can be baked and cooled 1 week ahead and kept at room temperature in an airtight container. Fill when ready to serve.
