1. Preheat the oven to 200 degrees Celsius (400 degrees Fahrenheit)/Gas 6.
2. Poke the sweet potato with a fork a few times, place on the oven rack, and bake in the preheated oven for 45–60 minutes, or until it’s soft when you squeeze it.
3. Remove from the oven and allow the sweet potato to cool in the foil. Once cool, peel the skin off (it should come off easily now).
4. Put the sweet potato ﬂesh into a medium-sized bowl and mash roughly with a fork to break it up.
5. Mix in the remaining ingredients (apart from the sea salt to serve) using a wooden spoon or a hand-held electric whisk, until smooth. For the ﬂufﬁest, best results, I use a hand-held electric whisk.
6. Portion into small jars or glasses and place in the fridge for at least an hour or overnight. Sprinkle the mousses with ﬂaky sea salt when you are ready to serve.