- For the blondies:
- 1 1/3 cups flour
- 1 tsp baking powder
- 1/2 tsp salt
- 3/4 cup granulated sugar
- 1/4 cup packed brown sugar
- 1/2 cup butter, melted and cooled
- 1 egg
- 1 1/2 tsp vanilla
- 1/3 cup rainbow sprinkles
- For the buttercream:
- 1/2 cup butter, at room temp
- 2 cups powdered sugar, sifted
- 1 tsp vanilla
- 1 to 2 tbsp heavy cream
- Additional rainbow sprinkles, if desired
- Preheat oven to 350 degrees and line one 9x9 inch pan with aluminum foil. Spray the foil with cooking spray.
- Mix together 1 tbsp of the flour with the rainbow sprinkles in a small bowl (this keeps them from bleeding too much into the batter!) Combine rest of the flour, baking powder, and salt in a bowl and whisk until well mixed.
- In the bowl of your stand mixer (or a large bowl with a hand mixer) beat both sugars and melted butter until smooth. Beat in eggs, one at a time, until fully incorporated, then beat in vanilla.
- On the slowest setting of your mixer, slowly stir the flour mixture into the butter/sugar mixture. Fold in the flour-coated rainbow sprinkles..
- Once the mixture is uniform, pour it into the prepared pan and bake at 350 degrees for 28-35 minutes, or until desired level of "doneness" is reached. (some people like their blondies a little undercooked, like yours truly!)
- Let cool in pan completely while you make the buttercream.
- Beat butter for a full three minutes until pale and fluffy, then beat in powdered sugar, one cup at a time, until frosting comes together. Beat in vanilla, followed by heavy cream (as needed) to adjust frosting consistency.
- Spread even layer of buttercream over top of cooled blondies. Top with additional lucky charms, if desired, and cut into bars.