Here you go, from this recipe on Epicurious (clearly I am procrastinating at work):
http://www.epicurious.com/recipes/food/views/Apple-Crisp-51203860
For the crisp topping:
1 cup all-purpose flour
2/3 cup packed dark brown sugar
3/4 teaspoon ground cinnamon
1/8 teaspoon salt
8 tablespoons (1 stick) unsalted butter, cut into 1/2-inch pieces and chilled
Make the crisp topping:
In a medium bowl, whisk together the flour, brown sugar, cinnamon, and salt. Add the butter pieces and use your fingers to rub the mixture together until the butter is incorporated and the mixture resembles coarse crumbs. Cover with plastic wrap and place in the refrigerator to chill while you prepare the apple filling.