1. Heat olive oil in a frying pan, fry the chopped onion slices and chopped garlic. Add the tomatoes and white wine and heat briefly.
2. Mix everything, and then transfer into a pot. Add the appropriate amount of stock (this may also be water or white wine) depending on the desired consistency of the soup. Add the clams with shells and the rosemary sprig into the simmering soup. Season with salt, pepper, herbes de Provence and chilli. Cook for about 15 minutes.
3. Serve with the Orzo pasta cooked earlier.