Preheat oven to 350°F and lightly coat a square baking pan with canola or coconut oil spray.

In a large bowl, combine oats, baking powder, salt, cinnamon, nutmeg, and walnuts.

In another bowl, whisk together milk, egg, applesauce, maple syrup, and vanilla. Pour into dry ingredients and mix well.

Slice peaches in half and discard pit. Cut peaches into slices or small dice, whichever you prefer. (You do not need to peel the peaches.) Mix peaches into the oat mixture.

Pour mixture into prepared pan, smooth the top, and bake for about 30 minutes, until firm and edges are brown.

Serve immediately with milk or maple syrup, or let cool completely to save for later. Store in the refrigerator and reheat individual squares in the microwave for about 45 seconds.