Copycat Little Debbie Cosmic Brownies

Ingredients

• 1/3 cup butter, softened
• 1 cup sugar
• 1 teaspoon vanilla extract
• 3 large egg whites, room temperature
• 2/3 cup all-purpose flour
• 1/2 cup baking cocoa
• 1/2 teaspoon baking powder
• 1/4 teaspoon salt
• GLAZE:
• 2 tablespoons water
• 1/4 teaspoon vanilla extract
• 2 tablespoons baking cocoa
• 2/3 cup confectioners' sugar
• 1/4 cup rainbow crunch sprinkles