Ingredients:

  • 1/2 cup (115g) unsalted butter, softened
  • 3/4 cup (150g) granulated sugar
  • 1 large egg, room temperature
  • 1 tsp (5ml) pure vanilla extract
  • 2 cups (280g) gluten-free all-purpose flour blend (with xanthan gum)
  • 1 tsp (5g) baking powder
  • 1/4 tsp (1.5g) fine sea salt
  • 1/2 cup (115g) unsalted butter, softened
  • 2 cups (240g) powdered sugar, sifted
  • 2 tbsp (30ml) heavy cream
  • 1 tsp (5ml) pure vanilla extract
  • 10g rainbow sprinkles

Instructions:

  1. Preheat your oven to 350°F (175°C). Line a 9x9 inch baking pan with parchment paper, leaving an overhang on the sides for easy removal.
  2. In a large bowl, beat the softened butter and granulated sugar on medium-high speed for 2-3 minutes until light and fluffy. Add the egg and vanilla extract, beating until fully incorporated and smooth.
  3. In a separate bowl, whisk together the gluten-free flour, baking powder, and salt. Gradually add the dry ingredients to the wet mixture on low speed, mixing just until no streaks of flour remain.
  4. Press the dough evenly into the prepared pan using a spatula. Bake for 18–22 minutes until the edges are pale golden and the center is set but slightly soft. Remove from the oven and let the bars cool completely in the pan.
  5. Beat the softened butter until creamy. Gradually add powdered sugar, vanilla, and cream, beating until the frosting is velvety and holds a peak.
  6. Spread the frosting evenly over the cooled bars. Top with sprinkles and slice into 16 squares.