Directions

1. In a bowl, whisk together flour, cocoa, baking soda, and salt; set aside. In another bowl, stir together butter, sugar, and egg. Add flour mixture, and stir until a dough forms.
2. Divide dough in half; roll out between two sheets of parchment paper to a 1/4-inch thickness. Stack on a baking sheet, and refrigerate until firm, about 30 minutes.
3. Preheat oven to 350 degrees, with racks in upper and lower thirds. Line two baking sheets with parchment. Using a 2-inch cookie cutter, cut dough into rounds. Place on sheets, 1 inch apart. Bake until cookies are firm and fragrant, 8 to 10 minutes, rotating sheets halfway through. Transfer to wire racks, and let cool.
4. Spread half the cookies with 1 tablespoon Cream Filling; top with remaining cookies. (To store, refrigerate in an airtight container, up to 5 days.)