Preheat oven to 350°F.
Mix apples and cranberries with 2 tablespoons flour until coated. (For best results, do this in a gallon-size zip-top bag.) Add in sugar, and continue to mix until evenly coated. Pour the flour- and sugar-coated fruit into an 11- x 7-inch casserole dish.
In a separate bowl, mix oatmeal, remaining flour, pecans, brown sugar, and melted butter until it resembles a crumble. Spoon the crumble over the fruit. Bake uncovered for 45 minutes.
