Makes 1 1/2 a normal filling recipe - which i cook in one pie)
8 apples
1 1/2 cups white sugar
3 tab flour
3/4 tsp cinnamon (got to 1 if you like it cinnamon-y)
1/2 tsp salt
1 1/2 tab white vinegar
butter
lemon juice - apx 1 1/2 tab
Peel core and slice apples into water with lemon juice added - while dough chills (i make my own)
When ready to assemble pie - roll out bottom crust and drain apples (they are only in water for about 20 minutes from start to finish)
Put cinnamon, flour and salt into large mixing bowl and mix together, then add vinegar and work it in with fingers...will sort of make crumbles. Add apples shake, stir, etc to coat with crumbled mix. Immediately fill bottom crust, and dot with icy cold butter.
Roll out top, place it over filling, cut slits for venting, and chuck into preheated 400 degree oven.
The vinegar makes a nice sweet tart filling, the butter adds richness, and if you work quickly, the sauce will be nice and thick and not runny.
I think one of the biggest secrets to a nice filling is working fast and not letting the apples stand with the cinnamon mixture. Also cutting steam vents.
A friend has tried subbing part of the white sugar with brown sugar and it works well too.
Ina's recipe here:
http://www.foodnetwork.com/recipes/ina-garten/deep-dish-apple-pie-recipe/index.html