Preheat the oven to 200°C/400°F/gas 6. Break the garlic up into cloves and peel and cut the onions into 3cm wedges. Halve and lay the tomatoes in a large roasting tray, cut-side up, then scatter over the unpeeled garlic cloves and onion wedges. Sprinkle with oregano, season with salt and pepper, and drizzle with olive oil. Roast in the hot oven for 50 minutes to 1 hour, or until the tomatoes are soft and sticky.⏱ 60 min
Scrape everything from the tray into a large saucepan. Pick out the garlic cloves and squeeze the soft flesh into the pan, discarding the skins. Pour in the stock then roughly chop and add the basil stalks with most of the leaves. Cut the ciabatta loaf in half and tear one half into the soup. Bring to the boil, then simmer for 10 minutes.⏱ 10 min
Meanwhile, put a griddle pan on a high heat. Slice the remaining ciabatta and griddle until lightly charred on both sides. Add a splash of red wine vinegar to the soup, then blitz with a hand blender until fairly smooth. Ladle into bowls, drizzle with extra-virgin olive oil and scatter with the remaining basil leaves. Serve with the slices of griddled ciabatta.
Jamie's tip: Ciabatta works brilliantly in this recipe, but it's also a great way to make use of your stale bread – save it up and use it to make this soup, or turn it into delicious croutons, breadcrumbs or toasts for things like pate, pickles or houmous.