Preheat your oven to 150°C/300°F.
Gently heat the rhubarb and apples on a medium-low heat in a saucepan, adding 1-2 tbsp water and stirring frequently until the mixture begins to bubble.
Continue to cook until the fruits have softened and disintegrate when touched with a spoon (about 15-20 minutes).
Remove from the heat and stir in maple syrup or coconut nectar. Set aside.
Mix the ground almonds, oats, coconut sugar and cinnamon in a large bowl until all ingredients are combined.
Rub the coconut oil into the mixture with your hands until it resembles a breadcrumb-like texture.
Spoon the fruit mixture into an oven-proof baking dish, and sprinkle the crumble mixture on top.
Bake for 20 minutes, until the top is lightly browned and the fruit bubbling.
Serve immediately with ice cream of coconut whipped cream. Enjoy!