Preheat oven to 350°F. Line two baking sheets with parchment paper.
Whisk flour, cornstarch, baking powder, baking soda, and salt in a medium bowl.
Beat butter, cream cheese, and sugar until light and fluffy, about 2 to 3 minutes.
Blend in vanilla and almond extract until smooth.
Add dry ingredients in two additions, mixing just to combine. Drizzle in milk to form a soft dough.
Fold in the sprinkles gently so they stay intact.
Scoop tablespoon-sized portions, roll into balls, then coat in extra sprinkles.
Chill the scooped dough on the sheet for 15 minutes to reduce spread.
Bake 10 to 12 minutes until edges look set but centers are pale.
Cool 5 minutes on the sheet, then transfer to a rack to finish cooling.