Chocolate-Tahini Linzer Cookies

Preparation Whisk flour, cocoa powder, baking powder, and 1 tsp. salt in a medium bowl to combine. Beat granulated sugar and butter in the bowl of a stand mixer fitted with paddle attachment on medium-high speed until light and fluffy, about 4 minutes. Add egg and vanilla and beat to incorporate, about 1 minute. Reduce speed to low and add dry ingredients. Beat just until dough comes together. Divide in half and pat each into a disk; wrap tightly in plastic. Chill just long enough that dough is rollable and no longer sticky, about 30 minutes. Working one at a time, roll out dough between 2 sheets of parchment paper until 1/8" thick. Slide onto baking sheets, still sandwiched between parchment, and chill until very firm, about 1 hour. Place racks in upper and lower thirds of oven; preheat to 350°F. Carefully peel away top sheets of parchment from dough and punch out cookies with larger cutters. Punch out centers of half of cookies with smaller cutters. Carefully transfer whole cookies with a spatula to a parchment-lined baking sheet, spacing 1" apart. Sprinkle remaining cut-out cookies with sanding sugar, then transfer to another parchment-lined baking sheet. Bake cookies until edges are set, 7–10 minutes. Let cool on baking sheets. Repeat process with scraps (chill dough again before punching out shapes). Melt chocolate and tahini in a bowl in a microwave in 20-second bursts, stirring after each, until chocolate is melted (or melt in a heatproof bowl set over a saucepan of simmering water; do not let bowl touch water). Stir to combine and season with salt. Spread filling over whole cookies; top with cut-out cookies. Do Ahead Cookies can be assembled 5 days ahead. Store airtight at room temperature.

Preparation Whisk flour, cocoa powder, baking powder, and 1 tsp. salt in a medium bowl to combine. Beat granulated sugar and butter in the bowl of a stand mixer fitted with paddle attachment on medium-high speed until light and fluffy, about 4 minutes. Add egg and vanilla and beat to incorporate, about 1 minute. Reduce speed to low and add dry ingredients. Beat just until dough comes together. Divide in half and pat each into a disk; wrap tightly in plastic. Chill just long enough that dough is rollable and no longer sticky, about 30 minutes. Working one at a time, roll out dough between 2 sheets of parchment paper until 1/8" thick. Slide onto baking sheets, still sandwiched between parchment, and chill until very firm, about 1 hour. Place racks in upper and lower thirds of oven; preheat to 350°F. Carefully peel away top sheets of parchment from dough and punch out cookies with larger cutters. Punch out centers of half of cookies with smaller cutters. Carefully transfer whole cookies with a spatula to a parchment-lined baking sheet, spacing 1" apart. Sprinkle remaining cut-out cookies with sanding sugar, then transfer to another parchment-lined baking sheet. Bake cookies until edges are set, 7–10 minutes. Let cool on baking sheets. Repeat process with scraps (chill dough again before punching out shapes). Melt chocolate and tahini in a bowl in a microwave in 20-second bursts, stirring after each, until chocolate is melted (or melt in a heatproof bowl set over a saucepan of simmering water; do not let bowl touch water). Stir to combine and season with salt. Spread filling over whole cookies; top with cut-out cookies. Do Ahead Cookies can be assembled 5 days ahead. Store airtight at room temperature.