In a large bowl mix the together the flour, sugar, butter, oatmeal, 1 cup of brown sugar, and 2 tsp of cinnamon. Mix everything together using your hands until it's turned into small pebble-sized clumps of dough.
Peel and core the apples, slicing them into thin strips. Once you have enough apple slices to fill a 9 by 13 glass pan to just under the rim, mix the apples with 1 tsp of cinnamon and the remaining 1/4 cup of brown sugar.
After you've mixed the apples and brown sugar together, pour the flour mixture over the top, making sure to spread it evenly across the entire pan.
Bake in a 350°F oven for 50 to 60 minutes or until the crisp mixture turns a nice golden brown and the apples have lost their crispness, but still, have somebody.
This crisp is delicious on its own, served with whip cream, or with ice cream.