Cream the butter and sugar in a mixing bowl until light and fluffy, about 3-5 minutes.
Add the egg, egg yolk, almond extract, and vanilla extract. Mix until fully incorporated.
In a separate bowl, whisk together the flour, baking powder, and salt. Gradually add to the wet ingredients and mix until just combined.
Wrap the dough in plastic wrap and refrigerate for at least 1 hour.
Preheat the oven to 350°F (175°C) and line baking sheets with parchment paper.
Scoop tablespoon-sized portions of dough, roll into balls, and place on baking sheets.
Bake for 8-10 minutes, until edges are lightly golden. Centers may look slightly underbaked.
Cool on baking sheets for 5 minutes before transferring to a cooling rack.
For frosting, mix powdered sugar, meringue powder, and water until smooth and glossy.
Once cookies are cool, decorate with frosting and add sprinkles.
