Mix 1 cup brown sugar, salt, cinnamon and granulated sugar. Spread on the bottom of the slow cooker.
Place the apples on top. Try to make a solid first layer on the bottom. Then add remaining chunks on top.
With your hands, mix the oats, 2/3 cup of loosely packed brown sugar, flour, butter, vanilla and cinnamon essential oil. Clump it together. (hope you don't get an itch right now) Sprinkle on top of the apples.
Cook on low for 4 hours, or high for 2 hours.
Turn off heat. Stir it. Then let sit for 1 hour to let the sauce thicken.
Notes
Serve with ice cream.ITEMS/INGREDIENTS USED IN RECIPE - If you are interested in any of the items I may have used (or are similar to the items I used) in making this recipe, I have listed all or some of them above within the post. NOTE: These links are affiliate links of which I receive a small commission from the sale of certain item. This does not affect your price, it remains the same.