¾ cup unsalted butter (170g), softened
1 1/4 cups confectioners’ sugar (155g)
1 teaspoon pure vanilla extract
Pinch of salt
3 egg yolks at room temperature (large eggs)
2 ½ cups cake flour (310g)
Food colors
Sprinkles
Egg wash: 1 egg white & 1 teaspoon water