Start by tossing your salted butter, granulated sugar, and brown sugar into a large bowl. Whip them together until the mixture turns light, creamy, and fluffy.

Next, mix in your egg and vanilla extract just until everything comes together. No overmixing here, you want the dough soft and smooth.

In another bowl, combine your all-purpose flour, Dutch-processed cocoa, espresso powder (optional), and baking powder. Sifting the cocoa first helps keep the dough silky and prevents little clumps from showing up in your cookies.

Slowly fold the dry ingredients into the buttery mixture until it just forms a soft, manageable dough. It should be slightly tacky but easy to handle. Divide it into two portions, shape each into a disk, wrap in plastic, and chill in the fridge for about 40 minutes. This step is the secret to cookies that roll out evenly and hold their shape perfectly.

Once chilled, lay one dough disk on parchment and lightly flour the top. Roll the dough out evenly until it’s about 1/8 inch thick. Cover it with another piece of parchment and transfer it to a baking sheet. Repeat with the second disk, stacking it on top with parchment in between. Chill the whole stack again for about 40 minutes until firm, this makes cutting shapes neat and effortless.

Bring the oven up to 350°F (175°C), then prepare your baking trays with a layer of parchment. Cut your cookies using a 2-inch cutter, and for half of them, remove the centers with a smaller cutter, hearts, stars, or any fun shape you like. Don’t toss the scraps; chill and reroll them for extra cookies.

Bake for 8–10 minutes until the edges are set but the centers remain soft and tender. Let them cool completely on the sheets, resist the urge to move them too soon, or they might break.

Once cooled, spread a teaspoon of chocolate-hazelnut spread on the bottom of the flat side of each uncut cookie. Lightly dust the “window” cookies with powdered sugar, then sandwich them together. Enjoy!