Peel and finely dice shallots. Peel the carrots and cut into fine strips. Divide the broccoli into florets.
Drizzle the fish fillet with 2 tablespoons of lemon juice and cut into bite-sized pieces. Remove the intestines from the king prawns and drizzle with the remaining lemon juice.
Heat the fat in a saucepan and sweat the saffron in it while stirring. Deglaze with fish stock and stock. Add the cheese and cream to the broth, puree, bring to the boil and season. Add the broccoli and carrots to the soup and cook for 5 minutes. Add the fish fillet and prawns and cook for 10 minutes.