Preheat your oven to 375°F (190°C) and prepare an 8" x 8" baking dish by spraying it with gluten-free nonstick cooking spray, such as gluten-free coconut oil spray.

To create the topping, mix the crumb topping ingredients in a medium bowl using a fork until the mixture resembles chunky crumbs. Place it in the refrigerator while you prepare the apple filling.

In a large bowl, combine the peeled and chopped apples with lemon juice, milk, melted butter, pure vanilla extract, packed brown sugar, ground cinnamon, gluten-free flour, and salt. Stir until everything is well mixed.

Transfer the apple mixture into the greased baking dish, spreading it out into an even layer.

Evenly sprinkle the crumb topping over the apples.

Bake in the preheated oven for 30 to 35 minutes, or until the top is golden brown.

Once baked, remove from the oven and allow it to cool for 5 to 10 minutes before serving.

Store any leftovers in an airtight container in the refrigerator for up to 3 days. You can also freeze the apple crisp for up to 3 months. To reheat, thaw it in the refrigerator overnight and warm it in the microwave or a 350°F (177°C) oven for 15 to 20 minutes.