Heat the oven to 350°F and line two baking sheets with parchment paper. The parchment helps the bottoms bake evenly and keeps cleanup easy.
Whisk the flour, baking powder, and salt together in a bowl, then set the mixture aside. Mixing the dry ingredients first helps the leavening and salt distribute evenly through the dough.
Beat the butter until smooth, then add the sugar gradually and mix for about 1 minute before blending in the egg, vanilla extract, and almond extract. The mixture should look pale yellow, a little fluffy, and slightly aerated rather than heavy or greasy.
Mix in the flour mixture just until no dry streaks remain, then stir in 1/2 cup sprinkles by hand. Stop as soon as the dough comes together so the cookies stay tender and the colors stay bright.
Scoop 2-tablespoon portions, roll each one into a ball, and press the tops into the remaining 1/4 cup sprinkles on a plate. Keep the dough balls taller than wide so the cookies bake with thicker, softer centers.
Arrange the dough balls on the prepared baking sheets with space between them and bake for 9-11 minutes. The edges should look set while the centers stay pale, soft, and lightly cracked.
Set the baking sheets on wire racks to cool, then repeat with the remaining dough only after the pans have cooled completely. Warm pans can start melting the next batch before it bakes, which encourages spreading.