A great combination of the best sugar cookie you have ever had and the fluffiest white cake.
Preheat oven to 350 degrees.
Line a 9X9 baking pan with parchment paper. This will help you remove it from the pan and frost it later.
Cream together butter and sugar for about 3 minutes until fluffy. Beat in your egg, vanilla and heavy cream until combined.
Mix in your flour, baking powder and salt on medium just until combined. If adding sprinkles to the batter, you can fold them in at this point.
Spread your batter in the baking pan and bake for 20 minutes or until set, and the edges are lightly golden. Allow to cool fully before removing from the pan and frosting.
Cream butter for about 2 minutes and then add powdered sugar, heavy cream, vanilla and a pinch of salt. Beat on high until light and fluffy. This should take about 3 minutes. Remove the bars from the pan, frost, sprinkle and slice into 9 bars. Enjoy!