Bring a large pot of water, (with the 1 tbsp. of salt added), to a boil over high heat. Purée 1/2 cup of the walnuts and the cream in a blender until smooth. Set aside the remaining walnuts. In a large sauté pan, melt the butter with the olive oil over medium heat until bubbling. Sauté the onion, prosciutto, garlic and red pepper flakes until the onion is tender and the prosciutto begins to brown, 6-8 minutes. Deglaze the pan with the wine, stirring to dislodge any browned bits from the bottom of the pan. Continue cooking to reduce liquid by half. Stir in the stock, walnut purée, the 1/2 tsp. salt and pepper. Bring to a boil, and then simmer to a sauce-like consistency for 10-12 minutes. Melt the Gorgonzola and Parmesan cheese in the sauce. Cook the pasta in the boiling water according to the package directions. Drain and return to the pot. Pour the sauce over the pasta and simmer over low heat, stirring constantly until the pasta is well coated, for about 3 minutes. Turn the pasta out onto a warm serving dish, sprinkle with parsley and remaining 1/4-cup walnuts, and serve.
Ready in 30 min