Heat oven to 375°F. Spray a 9-inch square pan or 2-1/2 quart casserole dish with cooking spray.
Combine oats, baking powder and salt in a medium bowl.
Whisk milk, eggs, vanilla butter, cinnamon, sugar and banana. Add to oat mixture and stir to combine. Fold in berries. Pour into dish. Sprinkle pecans evenly over top.