01 - Preheat oven to 350°F. Line two baking sheets with parchment paper and set aside.
02 - Whisk together flour, baking powder, and salt in a medium bowl until thoroughly blended.
03 - Beat softened butter and granulated sugar in a large bowl on medium-high speed until light and fluffy, approximately 2-3 minutes.
04 - Add egg, vanilla extract, and almond extract if using. Mix until fully incorporated, scraping down bowl sides as needed.
05 - Gradually add flour mixture to wet ingredients, mixing on low speed just until dough forms. Avoid overmixing.
06 - Divide dough evenly into 4-5 separate bowls. Add a small amount of pastel gel food coloring to each bowl, mixing until uniform color is achieved.
07 - Using a tablespoon or cookie scoop, portion dough into 1-inch balls. Place balls 2 inches apart on prepared baking sheets.
08 - Gently press each dough ball with the palm of your hand to flatten slightly, ensuring even thickness.
09 - Bake for 10-12 minutes until edges are set but centers remain soft. Do not overbake for optimal texture.
10 - Let cookies cool on baking sheets for 5 minutes, then transfer to wire rack to cool completely before filling.
11 - Beat softened butter until creamy. Add powdered sugar, vanilla, salt, and milk. Beat on medium-high speed until smooth and fluffy, adding additional milk 1 teaspoon at a time if needed for spreadable consistency.
12 - Spread or pipe buttercream onto flat side of half the cookies. Top with remaining cookies, pressing gently to form sandwiches.
13 - Roll exposed edges of buttercream in sprinkles for decorative finish if desired.