01 -
Preheat oven to 190°C. Line two baking sheets with parchment paper.
02 -
In a food processor fitted with the S blade, or in a stand mixer using the paddle attachment, combine flour, cocoa powder, baking soda, baking powder, salt, and granulated sugar.
03 -
While mixing on low speed or pulsing, gradually add butter pieces followed by the egg. Continue mixing until the dough comes together into a cohesive mass, about 1 minute.
04 -
Divide the dough into 1-tablespoon sized balls and arrange on lined baking sheets, leaving 5 cm between each. Lightly dampen your palm and flatten each dough ball to approximately 3 mm thickness.
05 -
Refrigerate the trays of shaped cookies for at least 10 minutes to firm the dough before baking.
06 -
Bake for 9–10 minutes, rotating pans halfway to ensure even baking, until cookies are fragrant and fully set. Cool completely on baking sheets placed on wire racks.
07 -
In a stand mixer with paddle attachment, beat butter and vanilla on medium-low speed until combined. Scrape the bowl, then gradually add sifted powdered sugar and sea salt. Increase speed to high and beat for 2–3 minutes, until filling is light and fluffy.
08 -
Using a pastry bag or spatula, place a teaspoon of filling in the center of one cookie. Top with a second cookie of equal size and gently press to spread the filling evenly. Continue until all cookies are sandwiched.
09 -
Serve cookies the same day for optimal texture.