1. Make the Fruit Filling
Add the rhubarb, apple, maple syrup, and water to a small saucepan.
Bring to a boil, then lower the heat and simmer uncovered for 10–15 minutes. Stir now and then as the mixture cooks.
Once the fruit becomes thick and jammy, remove from the heat and transfer to a heat-proof bowl.
Stir in the lemon juice and Black Elderberry Elixir. Place the bowl in the freezer for about 30 minutes to cool.
2. Prepare the Oat Crumble
While the filling cools, mix the oats, almond meal, Adaptogenic Powder, baking powder, cinnamon, and salt in a large bowl.
Pour in the melted butter and maple syrup. Fold everything together until a moist, crumbly dough forms.
3. Prep Your Baking Tin
Grease and line an 8-inch (20 cm) square tin.
Preheat your oven to 350°F (175°C).
4. Assemble the Crumble
Press a little more than three-quarters of the oat mixture into the bottom of the tin, forming an even, firm layer.
Once the fruit filling has cooled, spread it gently across the base.
Crumble the remaining oat mixture over the top.
5. Bake
Bake for 30 minutes.
Let the crumble cool completely before lifting it out of the tin and slicing it into squares.
6. Store
Keep the crumble in an airtight container in the fridge for up to 4 days.