Old Fashioned Apple Crisp

This is one of my families favorites. One of my favorite shows is Barefoot Contessa on Food Network. I love Ina! She makes complicated looking recipes look sooooo easy! Anyways, this is really a fantastic desert either on it's own or with vanilla ice cream (I suggest eating it with the ice cream - yummmmmmy). Things you need:

The filling:
5 pounds McIntosh or Macoun apples (I use Granny Smith)
Grated zest of 1 orange
Grated zest of 1 lemon
2 tablespoons freshly squeezed orange juice
2 tablespoons freshly squeezed lemon juice
1/2 cup granulated sugar
2 teaspoons ground cinnamon
1 teaspoon ground nutmeg

For the topping:
1 1/2 cups flour
3/4 cup granulated sugar
3/4 cup light brown sugar, packed
1/2 teaspoon kosher salt (I've used iodized and not had a problem)
1 cup oatmeal
1/2 pound cold unsalted butter, diced (again, I've used margarine with no problems)

Preheat the oven to 350 degrees F. Butter a 9 by 14 by 2-inch oval baking dish.
Peel, core, and cut the apples into large wedges. Combine the apples with the zests, juices, sugar, and spices. Pour into the dish.

To make the topping, combine the flour, sugars, salt, oatmeal, and cold butter in the bowl of an electric mixer fitted with the paddle attachment. Mix on low speed until the mixture is crumbly and the butter is the size of peas. Scatter evenly over the apples.
Place the crisp on a sheet pan and bake for 1 hour until the top is brown and the apples are bubbly. Serve warm.