Step 1

Heat the oil in a medium non-stick frying pan over medium-low heat.

Step 2

Add the sweet potato and onion and cook for 6-8 minutes or until softened. Add the zucchini and cook for a further 5 minutes.

Step 3

Whisk the eggs with salt and cracked black pepper and add to the sweet potato mixture. Turn heat to low and cook for 10 minutes or until just set.

Step 4

Meanwhile, heat an oven grill to medium-high. Sprinkle frittata with parmesan and place pan under preheated grill until the top is golden. Sprinkle with thyme leaves, slice into wedges and serve immediately.