INGREDIENTS
1/2 cup
unsalted butter, softened to room temperature
3/4 cup
granulated sugar
1
large egg + 1 egg yolk1
2 tsp
vanilla extract
1
and 1/2 cups (190g) spoon & leveled all-purpose flour
1/4 tsp
salt
1 tsp
baking powder
1/2 tsp
baking soda
1
and 1/2 teaspoons cornstarch
1/2 cup
rainbow sprinkles (not nonpareils)2
3/4 cup
unsalted butter, softened to room temperature
2
and 1/4 cups (270g) confectioners' sugar
3 tbsp
heavy cream or half-and-half3
1 tsp
vanilla extract
salt,
food coloring for frosting (I used 1 drop red for this pink frosting)
extra sprinkles for decorating on top