In a food processor, combine the crawfish, shrimp, shallots, cream, brandy, salt, cayenne, and pepper. Turn the mixture into a mixing bowl. Stir in the rice and parsley.
Using the feeding tube on a mixer, stuff the seafood mixture into the casings to make 3-inch links. Bring a large saucepan of salted water up to a boil. Add the peppercorns, onion, lemon slices and bay leaf and cook for 2 minutes. Add the sausage and poach until firm to the touch and plump, about 5 minutes. Remove from the water and let cool. In a large saute pan, over medium heat, melt the butter. Pan-fry the sausage for 3 to 4 minutes on each side. Remove from the pan and keep warm.
To serve, spoon the sauce in the center of each plate, and top with sausages. Serve immediately with Mustard Cream Sauce.
Yield: 8 servings