Pre-heat oven to 350F. Lightly butter an 8 inch (20cm) round or square baking pan.
FOR THE CRUMB MIXTURE
In a small bowl whisk together the flour, brown sugar, cinnamon and salt. Add the softened butter and combine to form large crumbs. Set aside.
FOR THE APPLE MIXTURE
In a large bowl add the apples as you slice them and drizzle a little of the lemon juice on them, mix to combine as you slice, (this keeps them from turning brown). Then add the cinnamon, brown sugar and corn starch if using, and gently combine well.
In the prepared baking pan add the apple mixture and top with the crumb topping. The pan will be very full but don't worry as the apples bake the mixture will flatten. Bake for approximately 45-60 minutes or until the apples are tender (using a toothpick).Let it cool for about 15 minutes then serve with a scoop of vanilla ice cream! Enjoy!
Notes
How to store the apple crisp?
The Apple crisp can be kept at room temperature for a day, after that it should be covered well and refrigerated. It will keep for up to a week in the refrigerator. The topping can be made in advance and stored in the fridge for up to 3 days or placed in a freezer safe bag or container and stored in the freezer for up to a month.
How to reheat it?
The crisp can be reheated in either a low oven for about 15 minutes or in the microwave.