Start by creaming together your butter and sugar until well combined and smooth. Add in your vanilla extract, mix, and set aside.
½ cup Softened Butter, 1 cup Sugar, 1 tablespoon Clear Vanilla
In a separate bowl, beat your egg whites on high until stiff peaks form. Set aside.
4 Egg Whites
In your final bowl whisk together your flour and baking powder until well combined.
1 1/2 cups Flour, 1 tbsp Baking Powder
To your butter and sugar mixture add your fluffy egg whites, mix until well combined. Add in your flour mixture and milk. Mix with a hand mixture until well combined and smooth.
½ cup Milk
Pour into a well greased 9x13 baking pan. Bake at 350 degrees for 20 minutes. Careful not to over bake and dry it out. Let cool.
Take your 3 cups and press into the baked cake upside down, as shown. Filling each cup with cake. You may need to do it twice if your cups are deep.
Cover the tops with an even and smooth layer of icing. Careful not to get it on the sides.
½ tub White Frosting
Press your cup, icing side down, into the sprinkles, as shown. Coating the top completely.
½ cup Rainbow Nonpareils Sprinkles
Serve and enjoy! No need to go to New York for this sweet treat! Make it at home.