Preheat your oven to 375 and a grease a 9x13 baking dish with cooking spray or olive oil.
Pour in your peeled and thinly sliced apples and squeeze your lemon juice over the apples.
In a small bowl, combine the brown sugar, white sugar, cinnamon, salt and mix. Pour that over the apples evenly and massage it in with the apples until all the apples are coated.
In a medium sized bowl make your crumble, combining the melted butter, flour, brown sugar, rolled oats and salt. Using your hands, mix until a crumble texture is created. Pour the crumble mixture over the apples evenly.
Put in the oven uncovered for 30-45 minutes, until bubbly and the apples are done.
Serve warm! I like to serve it with vanilla ice cream or some whip cream. You can leave in an airtight container for up to 3 days. Enjoy!:)