Boil or steam the sweet potato or pumpkin for about 4 minutes or until just tender. Drain well.

Place the eggs, milk, parsley (if using) and half the cheese in a medium-sized bowl and whisk with a fork until combined.

Season with pepper and set aside.

Lightly spray a 20cm (base measurement) non-stick frying pan with oil and heat on medium.

Add the ham and zucchini and cook for 5 minutes, stirring often, or until the ham starts to colour and the zucchini starts to soften.

Add the sweet potato and spring onions and cook, stirring occasionally, for 2 minutes.

Spread the mixture evenly over the base of the pan and arrange the tomatoes over the top, cut side up, pressing them gently into the vegetables.

Carefully pour the egg mixture over the vegetables and cook on medium heat for 5-8 minutes, or until almost set.

Meanwhile, preheat the grill on high.

Sprinkle the remaining cheese over the frittata and cook under the grill for 3-5 minutes until the egg mixture is just set and lightly golden on top.

Serve warm, or cool in the pan and serve at room temperature.

Recipes reproduced with permission from The Low GI Family Cookbook by Kaye Foster-Powell, Anneka Manning, Professor Jennie Brand-Miller and Philippa Sandall, Hachette Australia 2008.