Pre heat oven to 375 degrees. Grease a pie dish or 8X8 inch casserole dish with cooking spray.
Combine the dry ingredients in a large bowl. Whisk together the wet ingredients in another bowl.
Layer the peaches on the bottom of the pie dish. Pour in the steel cut oats mixture.
Bake for 50-55 minutes until the top is golden brown and the oatmeal is mostly set. It will continue to firm up as it cools.