Fruity Pebbles Funfetti Ice Cream Squares

Ingredients

• 1/2 cup unsalted butter, softened
• 3/4 cup sugar
• 1 large egg
• 1 egg yolk
• 2 teaspoons vanilla extract
• 1-1/2 cups all-purpose flour
• 1/4 teaspoon salt
• 1 teaspoon baking powder
• 1/2 teaspoon baking soda
• 1-1/2 teaspoons cornstarch
• 1 cup Fruity Pebbles cereal, divided use
• 2 cups Vanilla ice cream