Preheat oven to 350 F. In a large bowl, combine sliced apples, both granulated sugar and brown, sugar, cinnamon, and lemon juice. Spread mixture out into a greased baking dish.
In a medium bowl, combine flour, brown sugar, and oats. Cut butter into the mixture with a pastry blender until crumbly. Sprinkle over the apple mixture. Bake for 50-55 minutes.