Combine graham cracker crumbs, brown sugar, flour, salt, and baking powder in a bowl and whisk together. Either cut butter into chunks or use a large-hole cheese grater to grate it into the dry mixture. Use hands or pastry cutter to combine until crumbly. Set aside.
Apples
Core, peel, and slice or dice apples. Toss them with flour, sugar, cinnamon, nutmeg, and cloves, and spread out in a 9x13 baking dish. Sprinkle topping evenly on top.
Bake for about 35 minutes, until apples are tender (not mushy) and crumbly is golden brown. Cool down a little and then serve warm over vanilla ice cream.
Notes
If using all tart, green apples, increase brown sugar in filling by 4 tablespoons.