For the sweetpotato foam:
Wash, peel and cut the sweetpotatoes. Cook in poultry broth until tender. Puree with crème double and crème fraîche and strain through a fine sieve. Reduce the white port and Noilly Prat and add to the crème. Boil up, flavor and stir in butter flakes.
Mix 600 g of sweetpotato foam with eggs and egg yolk. Put into 4 big soup bowls and cover with foil. Let it set at 85 °C for 40 minutes.
Cut brick into strips, season scallops and wrap in brick strips. Let dry for a short time and fry in olive oil until it is crisp and brown.
Sauté sweetpotatoes in olive oil, deglaze with Burgundy vinegar and reduce. Pour on poultry broth, cover and steam slowly. Add raisins, barberries and capers and season to taste.
Add some olive oil and put aside. Fold in barberries under the warm sauce.
Fry thin slices of cauliflower slowly until brown, season with salt and pepper and add cilantro.
Place sweetpotatoes, scallops and cauliflower on the Royal and serve with the rest of the sweetpotato foam.