Made this for the filk last night.
4 cups sliced apples (I used apples and pears)
1/4 cup brown sugar, 1/2 tsp cinnamon, and juice from a lemon
Mix and dump in a 9x9 baking dish
Mix 1/4 cup flour, 1/4 cup oats and 3 tbs butter with a pastry cutter and sprinkle over the top.
Bake @ 350 for 45 minutes.