Preheat oven to 350°F. Arrange the sliced apples in a 9" x 13" baking dish and pour ¼ cup water into the dish. In a small bowl, whisk the granulated sugar, 1 tablespoon flour, cinnamon to combine and sprinkle the mixture evenly over the apple slices.
Place the rolled oats, flour, light brown sugar, baking soda and baking powder in a bowl and stir to combine. Pour in the melted butter and use a fork to incorporate it into the mixture. Sprinkle the topping evenly over the apples.
Bake for 50-60 minutes or until the crisp topping is golden brown and the apples are tender. Serve warm with vanilla ice cream.
Notes
To Store: Cover the baked apple crisp loosely and store in the fridge for up to 7 days.
To Freeze: Apple crisp can be frozen for up to 3 months in a freezer-safe container. When you are ready to serve it, allow the crisp to thaw in the fridge overnight before reheating.
To Reheat: Place in the oven at 350°F until heated through.