Preheat oven to 350°F and line baking sheets with parchment.
Cream butter and sugar until smooth.
Add vanilla, princess cake flavoring, and egg whites. Mix until combined.
Stir in flour, baking powder, and salt.
Fold in sprinkles.
Scoop dough onto baking sheets.
Bake 12–15 minutes, then cool completely.
For frosting, beat butter and cream cheese.
Add half the powdered sugar, vanilla, and milk. Mix.
Add remaining powdered sugar and beat until fluffy.
Color with pink food coloring.
Pipe frosting onto cookies.
Top with sprinkles.