Start by making the crumble topping. Melt butter and set aside.
To a mixing bowl add brown sugar, granulated sugar, flour, cinnamon, salt and oats.
Pour over the melted butter and mix with a fork until everything is incorporated and looks like wet sand.
Place bowl in the refrigerator while you move on to the apples.
Preheat oven to 350 degrees.
Peel and cut apples in 1/4 slices. Halve the apple slices.
To a pan set just under medium heat melt a tablespoon of butter. Add the apples.
To the apples add brown sugar, flour, cinnamon, salt and vanilla. Mix well and cook for 7 minutes.
Pour heavy whipping cream to the pan and stir. Turn heat off.
Grab the crumble topping from the refrigerator and break it up with a fork if it clumped together a lot. You want a mix of crumbles the size of peas and wet sand. Cover the apples in all of the topping.
Bake uncovered for 30 minutes.
Remove from the oven and cool for one hour. The juices will thicken up during this resting period. If you eat too soon it will be runny.