Preheat oven to 180 and bake sweet potatoes, skin on, for about 20 minutes until they are soft.
Peel the potatoes and mash then add the spring onion, season and mix. Generously layer the mash into the bottom of a soup bowl that can be baked in an oven.
Place a slice of goats cheese on top of the mash. In a bowl mix together the egg yolks and cream. Mix and season. Pour the savoury custard over the goats cheese and mash. Finally bake bowls in the oven at 180c for 15 minutes or until the custard is set on top. Eat immediately.