Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13 inch baking dish.
In a medium bowl, mix together the flour, baking powder, and salt. Set aside.
In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla. Beat in the flour mixture alternately with the milk. Fold in the peaches.
Pour batter into prepared pan. In another bowl, mix together the brown sugar, oats, and cinnamon. Stir in the melted butter, and sprinkle over the cake batter.
Bake in preheated oven for 40 to 45 minutes, or until a toothpick inserted into the center of the cake comes out clean.
Interesting Facts
Peaches are a good source of vitamins A and C, as well as dietary fiber.
The crumble topping on this cake can be made with any combination of nuts, oats, and spices.
This cake can be served warm or cold and can be stored in the refrigerator for up to one week.