Put the white fish to boil on low heat with 1 and 1/2 cup salted water, 2 tablespoons of oil and 1/2 bunch of parsley. Be careful not to over-boil the fish and have it come apart. Once ready, carefully transfer it to a warm platter.
Beat the egg yolks well with a full spoon of butter. Add a little lemon juice and salt to taste. Put the pot with the mixture on the stove on low heat and stir until the sauce thickens. Dilute the fish sauce with broth until you get the desired consistency.
Pour the sauce over the hot white fish. Make decorations as desired and serve.