Start by preheating the oven to 375 degrees F. Then, spray an 8" x 8" baking dish with nonstick cooking spray.
Wash and peel the peaches if desired. Slice one peach into about 15 - 18 sections. Cube more peaches to equal 1 cup.
In a large bowl, combine the old fashioned oats, brown sugar, cinnamon and baking powder. Add the melted butter and stir until well combined.
In a separate bowl, combine the milk with the vanilla.
Add the milk and vanilla mixture to the bowl with the oats and brown sugar. Stir to combine. Fold in the diced peaches.
Poor the oatmeal batter into the prepared baking dish. Spread the mixture so that is lays evenly. The batter will be a bit thin at this point.
Lay the sliced peaches over the top of the oatmeal batter. The oatmeal is now ready to bake. Place it in the oven and bake for 40 to 50 minutes, or until thickened and set.
Allow the oatmeal to cool for 5 to 10 minutes.
Notes
Cut the oatmeal into squares and serve. Add your favorite oatmeal toppings if you like. Maple syrup, whipped cream, additional brown sugar are all delicious on this baked peach oatmeal recipe.For a make-ahead breakfast, you can prepare the oatmeal the evening before, and cover the casserole dish with plastic wrap. Bake it the next morning for a super simple breakfast the whole family will enjoy.