Preheat oven to 200°C (fan-forced). Using spray oil or polyunsaturated margarine grease a 37cm-baking dish.
In a large pot of boiling water, cook the pasta according to packet directions, in the last 4 minutes add the cauliflower. Drain and set aside.
In a small saucepan cook the onion in the olive oil until softens, add the ham and garlic until fragrant.
Melt the margarine in a small saucepan, when it starts to bubble (careful not to burn) and stir in the flour. Cook, stirring continuously, for 1 minute, until the mixture forms a smooth paste.
Gradually pour in the milk, whisking constantly.
Return the pan to the heat and bring to the boil, still stirring or whisking until it thickens.
Remove from the heat and stir in the tasty cheese, set aside.
Thoroughly combine the white sauce, onion mixture and cooked pasta/cauliflower mixture in a large bowl, then spoon it into the baking dish, cover in the shredded mozzarella and bake for 20 minutes or until the top is golden.
Serving Size 250g
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.