1 stick softened butter
1 cup raw sugar or dehydrated cane juice (other sugar or substitute will also do; can cut amount by about a 1/4 cup if desired)
3/4 cup oats (not instant)
3/4 cup whole wheat flour (can substitute white unbleached)
1 teaspoon cinnamon, as fresh as possible
1/2 teaspoon each of cardamon and nutmeg (allspice and ground cloves are optional)
Mix completely until there are no lumps of butter; should be the texture of coarse meal.
Peeling apples is optional, but the texture with peel seems a little funny to me, and also requires more work in removing wax if you buy apples at a grocery store.