01 - Whisk together flour, baking powder, and salt in a medium bowl until well combined.
02 - Beat softened butter and granulated sugar in a large bowl until light and fluffy, approximately 2-3 minutes.
03 - Mix in egg, vanilla extract, and almond extract (if using) until fully incorporated.
04 - Gradually add dry ingredients to wet mixture, mixing on low speed just until combined. Do not overmix.
05 - Divide dough in half, shape into disks, wrap in plastic wrap, and refrigerate for at least 1 hour.
06 - Preheat oven to 350°F. Line baking sheets with parchment paper.
07 - Roll out dough on lightly floured surface to 1/4-inch thickness. Cut with shamrock or round cookie cutters.
08 - Place cookies 1 inch apart on prepared sheets. Bake for 8-10 minutes until edges just begin to turn golden.
09 - Let cookies rest on baking sheet for 2 minutes, then transfer to wire rack to cool completely.
10 - Mix powdered sugar, milk, and vanilla extract until smooth. Add green food coloring to achieve desired shade.
11 - Ice cooled cookies and add sprinkles. Allow icing to set before serving.