BRING LARGE PAN OF WATER to boil for pasta and add salt to taste. If pasta is dried, add it at this time. If it's fresh, wait until you've put together sauce ingredients. Have ready heated serving bowl or plates. Roughly mix ricotta cheese, butter, walnut oil, quarter cup walnuts and grated Parmesan cheese. Thin with half-and-half, stir in herbs and season with salt and pepper. Transfer mixture to wide skillet. About the time pasta is done, gently warm sauce over low flame. Cook and drain pasta and add it directly to pan with ricotta mixture. Toss everything together well, then place in heated bowl. Scatter remaining walnuts over pasta and sprinkle with grating of Parmesan cheese and plenty of ground pepper. DEBORAH MADISON PRODIGY GUEST CHEFS COOKBOOK