Step 1

Add butter and onion to pot, and sauté onions until soft.

Step 2

Add flour and gradually add milk and water simultaneously until desired thickness of sauce is achieved.

Step 3

Add cheese to the sauce.

Step 4

Add tuna and corn.

Step 5

Add salt and pepper, lemon juice, nutmeg and parsley.

Step 6

Cook pasta and add to sauce.

Step 7

Pour sauce mixture into casserole dish, sprinkle corn flake crumbs on top and bake at 200C for approximately 20 minutes.