Pre-soak your Irish moss for at least 24hrs. When it's ready, blend it up in the blender jug with 1 cup (250 ml) water. It won't purée completely, but it should break down quite considerably. When you're satisfied it's as broken down as it's going to get, you're ready to add the remaining ingredients. If it's not warm, and your coconut oil is hard, you're going to need to melt it to soften it a little. If it's already semi-liquid, you don't need to worry. Peel the grapefruits, and put all the flesh in the blender. Add in the lecithin, coconut sugar, and melted coconut oil. Blend it all up to a liquid and pour it into a large serving dish.

Next you're going to make the cream. Put everything in the blender together: the avocado flesh, acai, strawberry powder, strawberry essence, honey, and water. Blend to a cream. If your avocados are big, you may need extra water. Take spoons of the mixture and cover your grapefruit mousse with splodges of it. As the cream is heavier than the mousse it will sink a bit but that's not a problem, that's what gives it a sunset effect. Or if you're feeling artistic, you could put the cream in a piping bag and pipe it in patterns over the mousse. When you're done, put it in the fridge to set: it will take at least 4 hrs. It will keep for up to four days in the fridge.