Cook spaghetti to desired doneness as directed on pkg. Drain; rinse with hot water.
heat oven to 350. Grease 10 inch pie pan or 9 inch square pan. In large skillet, brown ground beef with celery;d rain. Stir in prepared spaghetti sauce and mushrooms. Simmer 15 minutes, stirring occasionally.
Mix cooked spaghetti, eggs, 1/4 cup of the Parmesan cheese and garlic salt; toss lightly. Put spaghetti mixture in prepared pan forming a crust. Pour meat mixture over spaghetti. sprinkle with remaining Parmesan cheese. Bake at 350 for 25 to 30 minutes or til crust is set and top edge is lightly browned. Let stand 5 minutes before serving. Serves 6