Frittata à la ratatouille with feta cheese dip

Traditional ratatouille is a French stew. Here, the typical ingredients are made into a frittata which also tastes great cold, so it is perfect for preparing in advance.

1. Wash and trim the aubergines, cut into 0.5-cm-thick slices and season with salt, then leave to stand for about 10 minutes. In the meantime, peel the onion and cut it into rings crosswise, then peel and finely chop the garlic. Sauté the onion in 1 tbsp of oil for 7–8 minutes until soft and briefly add the garlic. Wash and trim the courgettes and cut them into 0.5-cm-thick slices. Take the onions and garlic out of the frying pan, add the remaining oil and the courgette and fry on both sides over a high heat for about 1 minute until al dente. Season with salt and pepper and remove from the pan.  
2. Quickly rinse the aubergines, pat them dry and brush with 1 tbsp of oil. Then fry them over a high heat for approx. 3 minutes, brush the top again with 1 tbsp of oil, turn over and fry for another 3 minutes.  
3. Whisk the eggs with water, salt, pepper and chilli. Wash the thyme and shake it dry, pluck the leaves and stir into the egg mixture. Wash the tomatoes and cut into 1-cm-thick slices.  
4. Heat the remaining oil in a frying pan. Lay the tomato slices in the bottom of the pan. Pour a third of the egg mixture over them and spread the vegetables on top. Pour over the remaining egg mixture, cover and leave for about 30 minutes over a low heat until it solidifies. 
5. Wash the basil, shake dry, then roughly chop with the tender stems. Set a few leaves aside. Peel and chop the garlic. Wash the lemon in hot water, dry it and grate 2 tsp of zest. Crumble the feta and blend to a purée with the yoghurt, basil, garlic and lemon zest. Season with salt and plenty of pepper.  
6. Turn the frittata out onto a large plate and cut into wedges. Garnish with the dip and basil leaves.