Preheat oven to 180°C (350°F). Grease a 9-inch x 13-inch dish or two smaller baking dishes if needed. Set aside.
Prepare the apples
Peel, core, and cut the apples into uniform slices, about 1/4 inch thickness. Cutting the slices thin and evenly ensure juicy, fast cooking crisp with soft apples. If you cut the apples too thick, the cooking will be longer and it will dry the crisp topping.
Place the sliced apples into a large mixing bowl and toss with lemon juice, maple syrup, cinnamon, and nutmeg (if you love nutmeg, otherwise add more cinnamon or cardamom).
Stir well to cover all the apple slices with the sweet mixture.
Arrange the apples into one baking dish (9 inches x 13 inches) or 2 smaller oven baking dishes if you don't have a perfect size. Lay 2-3 layers of apple slices, not more, this is the best thickness for fork-tender maple-glazed apples with a crunchy topping. If you overlap too many apples, you will have to bake your crisp longer, the topping will dry out and the filling may be watery.
Set the baking dishes aside while you are making the crisp.
Make the topping
In a large mixing bowl combine all the topping ingredients: rolled oats, chopped walnuts, almond flour, shredded coconut, maple syrup, avocado oil, and cinnamon.
Massage the batter with your fingers to create a consistent crumble. The texture should be wet but crumbly.
Assemble the apple crisp
Sprinkle the topping evenly onto the apples until no more left. Don't spread or pack the topping using a spatula or it will be more like a cobbler recipe and the topping won't create crunchy cookie crumble pieces.
Bake in medium rack of your oven for 30-45 minutes. If you are using 2 small dishes, you can bake both dishes at the same time one in the center rack, and one in the rack just under.
Check the cooking after 25 minutes and every 10 minutes until it is cooked. You know a crisp is ready to go out of the oven when the bottom layer is bubbling, the apples are soft and juicy and the surface of the crisp is golden brown and crispy. The wider the pan is, the faster it cooks so always have an eye on your baking time to achieve your favorite texture.
Remove from the oven and cool for 10 minutes before serving.
Serve lukewarm with a dollop of dairy-free coconut yogurt or dairy-free vanilla ice cream.
Store on the counter at room temperature for 24 hours. Cover the dish with a towel to prevent dust from coming in.
Then store in the fridge for up to 4 days.
Rewarm the crisp
The next day your crisp topping will be soft, even softer if stored in the fridge. I recommend always rewarming your apple crisp in oven proof single-serve ramekin at 180°C (350°F) until the top crisp and the apples are lukewarm. Add an extra drizzle of maple syrup to prevent the apples from drying out.