While you work on the sauce, bring a large pot of cold water to a boil and begin cooking the sausage links in a medium skillet over low heat, cover and cook on both sides for 5-10 minutes or until browned and cooked through. Now begin making the sauce for the creamy Italian style gnocchi. Melt the butter over medium-low heat in a large skillet. Add shallots, and cook until translucent, about 2 – 3 minutes. Raise the heat to medium high and add mushrooms, thyme, and marjoram. Cook until mushrooms shrink a bit and begin to brown on the edges. Add the chicken stock, and reduce to 1 tablespoon. Add the heavy cream, salt, and pepper, and cook until cream thickens slightly.
Drop precooked gnocchi into the pot of boiling water, and cook until heated through and floating to the top, about 3 minutes. Lift gnocchi out of the water with a slotted spoon or skimmer, and transfer to the mushroom sauce, stirring until evenly coated. Cook for about 1 to 2 minutes. Plate the pasta and top with a few slices of Italian sausage. Drizzle with truffle oil and garnish with Parmesan cheese and marjoram. Enjoy!