Pre-heat oven to 200°C.

Finely chop onions and garlic (if using fresh garlic).

Heat olive oil in frying pan or wok. Add onion and garlic to heated pan.

Stir until golden brown, add tuna plus liquid to pan, simmer for about five to ten minutes or until mixture is warm.

Place butter or margarine in a microwave dish for about 40 seconds until melted.

Place flour, melted butter and milk into a microwave bowl. Stir and put in microwave on medium heat for about 2 minutes. Stir again. You may need to add more milk — sauce should be a smooth paste.

Add about 1 cup of grated cheese (remember to save some for sprinkling) on top of the sauce. Place mixture back into the microwave for about 1 ½ minutes.

Stir sauce and add to tuna mixture.

Place pasta in large microwave bowl, cover with water, cook on high for about 15 minutes. Drain pasta then add to tuna and sauce mixture.

Stir and simmer; add wine if desired. Cook for about five minutes.

Place mixture into an oven dish, smoothing mixture evenly into sides. Sprinkle remaining grated cheese over the mixture.

Place in oven, cook until cheese is melted and golden brown.