Dad's favorite Apple Crisp

Peel and slice 4 cups of apples,place in 8X8 baking pan. Mix: 3/4 cup oatmeal 3/4 cup brown sugar 1/2 cup flour 1 tsp cinnamon 1/2 cup butter (cut in with knife) Sprinkle over apples Bake at 350 for 30 min or until apples are fork tender. Serve with whipped cream or ice cream