In a saucepan, combine the water with 3 cups of the wine and a large pinch of salt and bring to a boil. Add the spaghetti and cook, stirring, until al dente. Drain, reserving 1/4 cup of the cooking liquid.

In a skillet, heat 2 tablespoons of the oil. Add the garlic and red pepper and season with salt. Cook over moderate heat for 1 minute. Add the remaining 1/4 cup of wine and the reserved cooking liquid and bring to a simmer. Stir in the pasta and cook until the liquid is nearly absorbed, 2 minutes. Add the parsley, nuts, the 1/2 cup of cheese, and the remaining 2 tablespoons of oil and toss. Season the pasta with salt and pepper and serve, passing grated cheese at the table.