Place the rhubarb, orange juice, lemon and berries in a large saucepan and bring to the boil over a medium heat.Simmer over medium heat until the rhubarb has softened (approximately 8-10 minutes).
Use a hand blender (or masher) and puree the mixture until smooth. Measure out 1 cup of pureed mixture and use.
Whisk the eggs, egg yolks, maple syrup, and 1 cup of the pureed fruit mixture in a heat proof bowl until the mixture is well combined.
Place the bowl over a pan of simmering water. Do not let the bottom of the bowl touch the water.
Once the mixture has started to warm, add the coconut oil 1 spoonful at a time. Whisk after each addition.Only add the next spoonful once the previous one has combined. Stir regularly.
This should take approximately 15 minutes. When done the mixture will be thickened and able to coat the back of the spoon.
Cool and place in a glass container. Store in the fridge.