Triple Berry Pie Squares

Ingredients

• 3 cups all purpose flour
• 1 cup granulated sugar
• 1 tsp. baking powder
• 1 cup 2 stickscold butter
• 1 egg
• 1/2 tsp. salt
• 1 tsp. cinnamon
• 1 tsp. vanilla
• 1 cup blackberries
• 1 cup raspberries
• 2 cups blueberries
• 4 tsp. cornstarch
• 1/2 cup granulated sugar