2 eggs, well beaten
3/4 c. evaporated milk
1/4 c. water
3/4 tsp. dry mustard
1 tbsp. grated onion
3/4 tsp. salt
3 c. cook macaroni
1 1/2 c. grated cheese
1 can tuna

Combine all ingredients in greased casserole. Bake at 375 degrees for 1 hour. Top with catsup if desired.