Bring the salmon broth to a boil with the butter and Cajun seasoning. Add a little black pepper. Add the flour all at once, stir quickly, and reduce to low heat. Cook for 5 minutes, stirring constantly, until the dough pulls away from the sides. Remove from heat. Add the eggs one at a time, mixing vigorously after each addition. Let cool slightly, then shape the quenelles.

Heat the lobster broth over low heat. Season with salt and pepper (I never salt my broths in advance).

Dissolve the cornstarch in a little cold water.

Add the cornstarch to the broth and whisk until thickened, then add the sour cream or crème fraîche and mix well.

Preheat the oven to 350°F (180°C). Place the quenelles in a baking dish.

Pour the sauce over the quenelles.

Sprinkle with parsley, then bake for 20 minutes.