At home I cored them but didnt bother to peel them, I simply sliced them into very fine slices and laid them in a buttered 10" tart pan in neat little swirls sprinkling brown crystal sugar ( a teaspoon total) and some raisins between the layers of apples. Six apples, sliced thinly gave me about three layers, but there were pretty big. I also added the juice of 1/2 a lemon over the top.
For the crumble, I mixed about 8oz of whole meal flour (probably about 6oz after sifting- pretty full of bran, rocks, etc.) with another 1/2 cup of oatmeal, a tsp of baking soda, 50 grams or so of brown crystal sugar. This I cut with maybe a stick of butter - no sticks here, hard to tell exactly how much. Once it was pretty well mixed, I added maybe a 1/4 cup of maple syrup (friends husband brought it back from NY- yeah pilots!!!) The texture was very crumbly and a little dry.
Baked it in the oven at some number of degrees for about an hour until it smelled good. The boys dont like it, so maybe I really should have asked those ladies over.
Forgive the bad measuring, lack of temperature instruction, I will try to keep better track from now on and quit switching from US to metric measures....