Tiramisu sandwich cookies

Ingredients:

Cookie

• 1.5 cups premium flour
• 1/4 cup cocoa powder
• 0.5 tsp baking powder
• 1/4 teaspoon of baking soda
• 1/4 teaspoon salt
• 1/3 cup milk
• 1 tbsp instant espresso powder
• 0.5 tsp vanilla extract
• 90 g unsalted butter, room temperature
• 3/4 cup granulated sugar
• 1 large egg

Filling

• 170 g mascarpone cheese, room temperature
• 110 g of cream cheese, room temperature
• 1/3 cup sifted powdered sugar, plus extra for sprinkling
• 0.5 tsp vanilla extract
• 1 tbsp coffee liqueur, such as Kahlua
• 1 tsp instant espresso powder

Preparation:

1. Position racks in the upper and lower thirds of the oven; preheat oven to 350°F (175°C).
2. Bake some cookies:
   
   In a medium bowl, combine the flour, cocoa powder, baking powder, baking soda, and salt. In a liquid measuring cup, combine the milk, espresso powder, and vanilla extract. In a large bowl, beat the butter and sugar with a mixer on medium-high speed until light and creamy, about 1 minute.
3. Add the egg and beat until smooth. Reduce mixer speed to low; beat in half the flour mixture, then the milk mixture, then the remaining flour mixture. Increase mixer speed to medium and knead until smooth, about 1 minute.
4. Drop 1 tablespoon of dough about 5 cm apart onto the prepared baking sheets (dip the spoon in water if the dough sticks); use your wet fingers to form even mounds.
5. Bake, rotating the baking sheets halfway through, until the cookies are set around the edges and the tops spring back when lightly pressed, about 10 minutes. Let cool on the baking sheets for 3 minutes, then transfer the cookies to wire racks to cool completely.
6. Prepare the filling:
   
   In a medium bowl, beat the mascarpone, cream cheese, 1/3 cup powdered sugar, and vanilla extract with a mixer on medium speed until smooth and light, about 1 minute. Transfer half of the filling to a separate bowl.
7. Mix the liqueur and espresso powder in a small bowl until completely dissolved, then add to the remaining filling and whisk. Transfer the fillings to separate large zip-lock bags and snip off the corner of each.
8. Turn half of the cookie over and pipe a circle of coffee filling along the edge of the cookie. Spread plain filling inside the coffee circle and top with the remaining cookie. Refrigerate until the filling sets, about 1 hour. Dust the cookies with powdered sugar.