I have and can give you the recipe, but this isnt my dish. Just to be clear on that. :)

Translated from the source (which doesn’t give exact amounts):

1. Rinse and dry your sweet potatoes.
2. Roast them in a charcoal bbq of 200C for roughly 1 hour with the lid closed; Rotate often.
3. Let them cool down until handleable and remove the peel.
4. Blend smooth in a food processor; add chicken stock as needed
5. Season to taste with salt and pepper.