Heat the oven to 375°. Combine the flour, G cup of the sugar, the brown sugar, and the butter in a bowl. Mix the ingredients with your fingertips to create pea-size crumbs. (Alternatively, pulse the mixture in a food processor 10 times or so.)
Combine the apple slices and cranberries in a large bowl. Mix the juice, remaining 2 tablespoons of sugar, and cornstarch in a small bowl. Pour the mixture over the fruit and toss well.
Spoon the fruit into a 2-quart baking dish and sprinkle on the flour mixture. Bake the crumble until bubbly and golden brown, about 40 minutes. Serves 6 to 8.