Place apples in a 9×13 inch baking dish. In a bowl, mix melted butter, flour, sugar, oats, and 1 tablespoon cinnamon to form a crumbly mixture. Sprinkle over apples. Dot with remaining 1/4 cup butter, and sprinkle with remaining 1 tablespoon cinnamon.
Bake 50 minutes in the preheated oven, until lightly browned and apples are tender.