Makes 615g.
Heat the oven to 390°F / 360°F fan.
Mix together the rhubarb, raspberries and 2 tbsp of the agave nectar and place into a baking dish.
To make the topping, mix the oats, Huel toffee flavour system, remaining 1 tbsp of agave nectar and walnuts. Rub in the coconut oil using your fingertips.
Cover the fruit with the crumble and bake in the oven for about 30 minutes until the topping is golden brown.