Sauté the crab with half the butter, add the chopped leeks and tomato paste, sauté with the flour and add some white wine.
Evaporate and cover with water, add the spices. Cook and reduce the mixture for 25 min.
Roast the carrots in the oven covered with aluminum, peel, and proceed to make a puree with the butter and sugar.
Add the puree to the broth, cook, and strain. It should be thick. Set aside.