Cut up peaches (leave the skin on-trust me). Place peaches in a buttered 8x12" baking dish. Combine flour with brown sugar, white sugar and cinnamon in a small bowl. Cut butter into sugar mixture until it is in tiny bits. You can do this with a food processor if you like.
Now, put the sugar and butter mix on tip of the peaches. Bake in preheated oven at 350F for 1 hr. or until topping is crisp and peaches are tender. Serve on its own or with vanilla ice cream. Don't tell how easy this is to make!