Brown beef in 3 Tbs. butter, add onions and sauté until golden. Mix meat and onions with ketchup and Worcestershire sauce. Season to taste with salt & pepper. Add as little beef stock and cook covered over low heat for 15 to 20 minutes. Beat egg yolks until light, whites until stiff. Beat yolks, cream remaining, 1/2 cup butter and garlic powder into mashed potatoes. Gently fold in beaten egg whites. Put meat mixture into casserole and top with potatoes, sprinkle with Parmesan cheese and bake at 350 degrees until puffed and browned.
In large heavy pan, lightly brown beef and onions in oil. Add tomatoes (with juice), tomato paste, water, parsley, salt, garlic powder, pepper and oregano. Simmer uncovered about 30 minutes. Mean while cook lasagna noodles as directed. In 9 1/2" X 13" baking pan spread about 1 cup of sauce, then alternate layers of noodles, sauce, cottage or ricotta cheese, mozzarella, Parmesan, hard-boiled eggs and zucchini ending with sauce, mozzarella and Parmesan. Bake at 350 degrees for 40 - 50 minutes or until slightly browned and bubbling.