Preheat oven to 350 degrees F.
Whisk together the dry ingredients. In a separate bowl whisk together the maple syrup half and half, milk, egg. Pour this into the bowl with dry ingredients, and stir to coat and combine.
Grease the bottom and sides of a high lipped casserole pan, approximately 7x11. Spread half of the oat mixture into the bottom, then top with half the peaches and half the pecans. Scoop the remaining oat mixture onto the top and evenly disperse to cover the peaches. It is okay to leave the liquid in the bowl, you'll use it.
Then top with pecans and remaining peaches, putting in a pattern if you like. Then pour the liquid left in the bowl evenly over everything. Drizzle melted butter over top.
Bake for 35-40 minutes, until liquid is absorbed and top is browned. Cut into squares and serve with a drizzle of cream or yogurt, and maple syrup.