Step 1Heat the oil in a small nonstick skillet over medium heat. When hot, add the shallots and garlic. Cook until warmed through, about 2 minutes. Add the cream, sage, 1/2 teaspoon of salt, the pepper and nutmeg. Stir well; simmer, uncovered, until slightly thickened, about 3 minutes. Set aside.
Step 2Bring a 4-quart pot of salted water to boil. Add the pappardelle. With about 6 minutes to go, add the cabbage.
Step 3Cook, uncovered, until the pasta is al dente, about 7 to 10 minutes total. Drain well; transfer to a large, shallow serving bowl. Toss with the cream sauce and 1/3 cup of cheese. Serve hot, garnished with sage sprigs. Pass grated Parmigiano-Reggiano cheese separately.