The Best Apple Tart

(like my title?)
This was a little tough, since I was supposed to be copying something I've never tasted! I thought I'd go for more of a European flavour - in my limited experience this means buttery and not too sweet. This was on the thin side, but I thought the "height" of it was perfect. I wanted something that actually was more of a tart, in case one day I actually own tart pans and could make little ones.
I happened to have leftover hazelnuts from Christmas, so I used those in the crumb topping. It tasted really good while I was snitching it, but after it was baked, I couldn't really taste them.
Oh, one important thing: I lost the paper that I was jotting things down on as I baked this. So, sorry in advance if you try this and it doesn't turn out. This is my guess.
Anyway, without anything farther, here is my recipe:

Crust:
1 C flour
1/2 C icing sugar
1/2 C butter
1 egg yolk
enough cream to make a soft dough
Mix flour and icing sugar and rub in butter with your hands. Leave some chunks. Mix in egg yolk and cream until soft but not too sticky. Use some extra flour to press dough into pan.
(I used an 8" springform pan)

Chop 4 large apples and place evenly on crust. Sprinkle generously with cinnamon.

Mix together the following and put on top of apples:
1/2 C ground hazelnuts
1/4 C brown sugar
1/2 C oatmeal that has been ground in a blender
2 Tbsp butter

Bake at 350F until crumbs are golden and you're sure crust and apples are done. Don't underbake it.

[I wouldn't bother with the caramel sauce I made. It was more like a butter sauce, and even though it was good, I would have preferred this without it.]

All in all, I would give this a very high rating, Thank you, Karla.
I loved the crust. I loved the topping. It was very buttery and not too sweet. Yum.