Preheat your oven to 180°C/Fan 160°C/Gas 4. Peel and finely slice the onions. Pour 1 tbsp olive oil into a large ovenproof frying pan and warm it to a medium heat. Slide in the onions and season with salt and pepper. Fry for 5 mins, stirring occasionally, till glossy and lightly browned. If the onion starts to colour too quickly, turn the heat down and add a splash of water.

While the onions fry, thickly slice the portobello mushrooms. Slice the chard leaves off the stalks. Finely shred the leaves and finely chop the stalks, trimming off any dry ends. Keep the stalks and leaves separate. Peel and grate 1 garlic clove.

Add the mushrooms, chard stalks and grated garlic to the onions and cook for 5 mins, stirring occasionally, till the veg soften and look juicy.

While the veg fry, crack the eggs into a bowl and add a good pinch of salt and pepper. Beat well.

Tip the chard leaves into the pan and stir to wilt them. Pour over the beaten eggs and swirl to coat the veg. Fry for 1 min, then slide the pan into the oven for 10 mins till the frittata is set. If your pan isn’t ovenproof, tip the veg into an ovenproof dish, pour over the beaten eggs, then pop into the oven.

While the frittata bakes, grate the remaining garlic clove into a mixing bowl. Grate in the lemon zest and squeeze in 1 tbsp lemon juice. Roughly chop the oregano leaves and add them to the bowl. Add salt and pepper and 1 tbsp olive oil and stir to make a dressing.

Slice the tomatoes and tip them into the bowl with the dressing. Add the rocket and toss to dress. Pile the salad onto 2 warm plates and serve with wedges of the frittata.