1 pound of rigatoni or similar pasta
1 large package (12 oz.) of fresh mushrooms, cleaned and sliced
1 large bag (10-12 oz.) of fresh baby spinach, washed well and stems removed
1 cup walnut pieces
3 tablespoons butter
1 small container (8 oz.) mascarpone cheese
1/2 cup freshly grated Parmesan cheese
salt and fresh ground black pepper
1/4 teaspoon freshly ground nutmeg or 1/2 teaspoon dried nutmeg.
**optional 1 whole chicken breast grilled and choppped
1. Put a large pot of water on to boil. (4 quarts or liters for a pound of pasta)
2. While the water is heating, carefully clean the mushrooms with a brush or damp towel, cut off the tough end of the stems and slice them. Avoid running the mushrooms under water as this makes them tough and chewy. Look for fresh, pre-sliced mushrooms to save time. Melt the butter in a large saucepan and saute the mushrooms on medium low. Once they start to exude moisture, season lightly with salt and pepper. Continue cooking until the mushrooms are a rich golden brown and some of the liquid has been cooked down.
3. Add the spinach and stir together until the spinach is just wilted.
4. Add the mascarpone cheese and 1/2 of the Parmesan cheese and blend well. Heat through. The mascarpone cheese will start to melt and thin out a bit as it warms up. Season with fresh nutmeg, salt and fresh-ground black pepper and turn the heat to low to keep warm.
5. When the water is at a rolling boil, add 1 heaping tablespoon of salt and drop in the pasta. Stir gently to keep the pasta from sticking. Cook according to the package directions until al dente (firm to the bite).
6. While the pasta is cooking, gently toast the walnuts in a small, dry saucepan on medium low heat. Set aside.
7. When the pasta is done, carefully reserve a 1/2 cup of the starchy pasta water and set aside. Drain the pasta and add it back into the hot pot, off the heat.
8. Add the mushroom and spinach sauce and toss everything together to combine. Add a splash of the reserved pasta water to smooth out the sauce to a silky consistency.
9. Plate the pasta and garnish with the toasted walnuts and the remainder of the Parmesan cheese. Serve immediately.