Makes 24 2-inch cookies
- ½ cup unsalted butter, at room temperature
- ½ cup icing sugar, sifted
- 3 large egg yolks
- 1 cup cake & pastry flour
- ¼ cup Dutch process cocoa powder
- 2 Tbsp cornstarch
- ½ tsp salt
- icing sugar, for dusting
- Beat the butter and icing sugar until smooth, then add the egg yolks all at once and beat until well combined.
- In a separate bowl, sift the flour, cocoa powder, cornstarch and salt. Add this to the butter mixture and stir until evenly combined. Shape the dough into a log about 2 inches in diameter, wrap and chill until ready to use.
- For icebox cookies, preheat oven to 325 °F. Line 2 baking trays with parchment paper.
- Cut the dough into slices about 1/8-inch thick and arrange them on the prepared baking trays. Bake for about 12 minutes, until they are no longer shiny. Once cooled, dust the cookies with icing sugar.
- The cookies will keep in an airtight container for up to 4 days.