Apple Crumble

I'll be honest, this was not my favorite recipe. After I made it, I read the comments (yes because I don't learn to do that first), and I noticed many people also found it too dry. Basically, probably not the way you want to go. But the apples turned out well, and when I first got it from the oven and ate it with greek yogurt, it was delicious. It has otherwise been nice to reheat and serve with greek yogurt for breakfast. I used my excess topping that I didn't put on the apples to make a granola pie thing by mixing in peanut butter and maple syrup. Take from all that what you will.

Filling
4 large Golden Delicious apples (about 3 pounds) [I used 4 or 5 smaller apples]
1/4 cup sugar
1 lemon, juiced [didn't have this, just sprinkled on some water]
2 tablespoons all-purpose flour
1/2 teaspoon ground cinnamon

Topping
1 cup walnuts or pecans, roughly chopped [didn't use this, but probably would be good]
1 cup all-purpose flour [too much! probably use 1/2 cup]
1 1/4 cups rolled oats [maybe start with 1 cup instead]
1/2 cup packed dark brown sugar
1 teaspoon ground cinnamon
Pinch fine salt
8 tablespoons (1 stick) cold butter, cut into small pieces
Vanilla ice cream, for serving, optional [or greek yogurt, like I had]

Position an oven rack in the center of the oven and preheat to 350 degrees F.

Peel, core, and slice apples into 1/4-inch slices [I didn't peel them because I don't mind having peels involved]. Place apples in a large mixing bowl and toss with sugar, lemon juice, flour, and cinnamon. Pour into a lightly greased 9 by 13-inch baking dish, and spread out into an even layer. Set aside.

In another large bowl, mix together the nuts, flour, oats, sugar, cinnamon, and salt for the topping. Using a pastry cutter or your fingers, gently work in the cold butter until pea-sized lumps are formed.

Top apples evenly with mixture and bake until apples are bubbly and topping is golden brown, about 45 minutes, rotating once halfway through cooking.