01 - Preheat the oven to 350°F. Line two baking sheets with parchment paper to prevent sticking and ensure easy cleanup.
02 - In a medium bowl, whisk together the all-purpose flour, baking powder, and salt until well combined. Set aside for later use.
03 - In a large bowl, beat the softened unsalted butter and granulated sugar together using an electric mixer until the mixture is light and fluffy, approximately 2-3 minutes.
04 - Add the large egg, pure vanilla extract, and almond extract if using. Mix until all ingredients are fully incorporated and smooth.
05 - Gradually add the flour mixture to the wet ingredients, mixing on low speed just until the dough comes together. Avoid overmixing to prevent tough cookies.
06 - Divide the dough evenly into 4-5 separate bowls. Add a different pastel gel food coloring to each bowl, mixing thoroughly until the color is uniform throughout each portion.
07 - Using a tablespoon or cookie scoop, portion the colored dough into balls approximately 1 1/2 inches in diameter. Place the dough balls 2 inches apart on the prepared baking sheets to allow for spreading.
08 - Gently flatten each dough ball with the palm of your hand to create an even thickness, ensuring uniform baking.
09 - Bake for 10-12 minutes, or until the edges are set but the centers remain slightly soft. Watch carefully to avoid overbaking, which will result in dry cookies.
10 - Allow the cookies to cool on the baking trays for 5 minutes before transferring them to a wire rack to cool completely. This prevents them from breaking apart while still warm.
11 - Beat the softened butter in a clean bowl until creamy. Add the sifted powdered sugar, vanilla extract, salt, and milk. Beat on medium-high speed until the frosting is smooth and fluffy. Add additional milk if needed to achieve spreadable consistency.
12 - Once the cookies have cooled completely, pipe or spread a generous layer of buttercream onto the flat side of half the cookies. Top each frosted cookie with a matching cookie to form sandwiches, pressing gently to secure.
13 - Roll the edges of the assembled sandwiches in sprinkles if desired for a festive presentation. Serve immediately or store in an airtight container.