• Preheat the oven to 350°F (180°C). Spray a 9x13 baking pan with nonstick spray and set aside.
• In the bowl of a stand mixer or with an electric hand mixer, cream together the salted butter and granulated sugar until light in color and fluffy in texture.
  1 cup (222g) salted butter, softened, 1 cup (230g) granulated sugar
• Scrape the sides of the bowl and add in the eggs, vanilla, and canola oil. Mix until combined.
  2 eggs, 2 tsp vanilla extract, 2 Tbsp canola oil
• Next, add the flour, baking powder, and rainbow sprinkles. Mix until a soft dough forms.
  3 cups (456g) all-purpose flour, 2 tsp baking powder, ½ cup (107g) rainbow sprinkles
• Press the dough into the prepared baking pan evenly.
• Bake at 350°F (180°C) for 15-18 minutes or until the dough has puffed up and the center no longer looks wet and glossy. Allow the cookie bars to cool completely before frosting.

Frosting

• First, melt the white chocolate chips in the microwave by heating them at full power for 30 seconds and then stirring. Repeat until the white chocolate is completely melted. Set aside.
  1/2 cup (200g) white chocolate chips, melted and cooled
• With a stand mixer or with an electric hand mixer, cream the butter.
  1/2 cup (111g) salted butter
• Alternate adding 1/2 cup of powdered sugar with just enough heavy cream to bring the mixture together. Repeat until all of the powdered sugar has been added. The frosting should stay thick.
  3 cups (321g) powdered sugar, ~1/4 cup (60mL) heavy cream
• Next, mix in the cake batter flavoring. Once incorporated, slowly mix in the melted white chocolate.
  1/2 tsp cake batter flavoring
• You can further adjust the thickness of your frosting by adding more heavy cream, if desired.
• Spread on the cooled cookie bar and top with sprinkles.
• Cut into bars and then top each bar with a dollop of whipped cream.
  whipped cream, if desired
• Store in the fridge and serve chilled. Enjoy!