Preheat the oven to 350 degrees F.
For the crumb topping: In a medium bowl, mix the flour, brown sugar, granulated sugar, cinnamon, nutmeg, butter and salt using a fork, or pastry cutter.
For the apple filling: In an 10-inch cast-iron skillet, heat the butter over medium heat. Add the apples a pinch of salt. Let cook for 2-3 minutes. Stir in the brown sugar, cornstarch, vanilla and lemon juice.
Spread the apples in the skillet evenly and add the crumb topping. Bake for 30-35 minutes or until the top is golden brown. Serve with a scoop of ice cream and a drizzle of salted caramel.