Apple Crumble with Vanilla Ice Cream

Name: Apple Crumble with Vanilla Ice Cream
Cuisine: American
Ingredients: 2 1/2 cups old-fashioned-oats; 1 1/2 cups (packed) golden brown sugar; 1 cup all purpose flour; (2 sticks) chilled, unsalted butter, cut into 1/2-inch cubes; Nonstick vegetable oil spray; 4 pounds large Granny Smith apples, peeled, halved, cored, each cut into 6 slices; 3 tablespoons fresh lemon juice; 1 tablespoon ground cinnamon; Vanilla ice cream