Preheat oven to 375°F and generously spray the inside of a 10-1/2 by 7 inch baking dish with cooking spray and place on a baking sheet. If you do not have that size-baking dish, a 9 by 13 pan is fine, just thinner. In a large bowl, mix together the oats, sugar, baking powder, salt, half the berries and half the chocolate. In another bowl, whisk together the milk, egg, butter, cinnamon flavor and pure vanilla. Add the oat mixture to prepared baking dish. Arrange the remaining berries and chocolate on top, add the banana slices to the top, pour the milk mixture over everything. Gently shake the baking dish to help the milk mixture go throughout the oats. Bake 35 to 40 minutes or until the top is golden brown and the milk mixture has set. After it has cooled, cover with plastic wrap and store in fridge. When ready for breakfast, heat in microwave for 1-3 minutes, or until warmed through.