my sister's famous apple crumb pie

This pie is like, the bee's knees. My sister makes it for all the typical holidays plus also whenever she is feeling especially generous... I normally save all the room in my stomach on Thanksgiving for this pie.... So so so good. I tried my hand at making it recently and well, I only had to text my sister and my mother about twenty-two times to figure it out. To say that I would never have survived as a 1950's housewife is quite an understatement. 
There is a pie crust recipe that I was also given but nah, store bought is fine by me! I've made the pie twice, once it went into the fridge and was baked the following day, and once it was baked right away, both times it was amazing. So. There you have it.

It's actually pretty straight forward.
For the apple pie filling combine the following.....
3 1/2 - 4 cups of apples (peeled and sliced)
1 cup brown sugar
2 tsp cinnamon
3 tbsp flour (more if you feel it's necessary)
For the crumb topping you combine the following....
1 cup flour
1/2 cup sugar
1/2 cup butter (softened)
Cinnamon to taste (or just till the crumbs are a nice shade of brown)
So you put the apples into the pie crust and then top with the crumbs and then you bake at 400° for 45-50 minutes. I laid a piece of tin foil over the top during baking because I was told it would keep the crumbs from getting too brown. Sure thing!
And then you eat it all.
You're welcome.