Preheat oven to 400 degrees. Prepare the crumble topping while oven preheats.
In medium bowl, mix together flour, oats, brown sugar, sugar, salt, and cinnamon. Cut in butter with a flat-faced knife (or two forks) until mixture is crumbly. Set aside.
Peel and chop 4 of the apples.
Add chopped apples, butter, brown sugar, and cinnamon to medium sauce pan and sauté on medium heat (about 8-10 minutes) or until apples are tender. Remove from heat.
Remove the tops off of remaining 4 apples and use spoon to core the insides. Discard the cores or save for another recipe. Scoop just enough to make a "bowl" for the remaining ingredients.
Fill hollowed apples with filling from the sauce pan.
Top with a hearty amount of crumble topping.
Put stuffed apples onto baking sheet and bake (about 10-15 minutes) or until crumble topping is crispy.
Serve warm (optional: top with ice cream and caramel sauce) and enjoy!