Mix the sliced apples with the lemon juice, cinnamon, and maple syrup.
Let the mixture macerate for 15-30 minutes.
Meanwhile, use a food processor to pulverize the walnuts, oats, pumpkin seeds, chia seeds, spices, and salt until they form a meal.
Add in the dates, maple syrup, and water.
Process until the mixture is well combined and begins to clump together.
Pour the apples into a small dish (I use a 7 x 5 inch Pyrex dish).
Using your hands, spread the crumble atop the apples.
Top with coconut whipped cream, if desired.