01 -
Heat oven to 375°F (190°C) and lightly grease a 9" cast iron skillet.
02 -
In a large bowl, combine sliced apples, lemon juice, granulated sugar, flour, cinnamon, vanilla extract, and salt. Toss gently with your hands to coat the apples evenly in the mixture.
03 -
Transfer the apple mixture into the greased cast iron skillet, spreading evenly.
04 -
In a medium bowl, combine flour, oats, brown sugar, cinnamon, cold cubed butter, and salt. Use your hands, a fork, or a pastry cutter to work the mixture until the butter is broken into pea-sized pieces.
05 -
Spread the topping in an even layer over the apples.
06 -
Bake for 30 minutes or until the apples are fork-tender and the crisp topping is dark golden brown.
07 -
Serve warm with vanilla ice cream.