• 4 red peppers (capsicums), cut in half lengthways and seeds removed
• 2 tablespoons olive oil
• 2 garlic cloves, lightly crushed with the flat of a knife
• 1 small red onion, sliced
• 4 ripe tomatoes, peeled and chopped, or 400 g (14 oz) tinned tomatoes, chopped
• 300 g (10½ oz) plain greek yoghurt
• 40 g (⅓ cup) pitted black olives, roughly chopped
• finely grated rind of 1 lemon
• leaves from 2 rosemary sprigs, finely chopped

Preheat the grill (broiler) to high. Line a large oven tray with foil and arrange the peppers, skin side up, in a single layer. Grill for about 30 minutes until the skin has darkened in places and swelled up and the peppers are soft. You might need to move them around on the tray so they are evenly grilled or remove the halves that are blackened and leave some in for longer.

Transfer the peppers to a bowl, cover with plastic wrap (or put in a plastic bag and seal) and leave to sweat for 10 minutes to make peeling easier. Peel off the skin.

Heat the olive oil in a large saucepan and sauté the garlic and onion for about 5 minutes. Add the tomato and cook until it begins to bubble. Add the pepper halves, tearing them into large chunks as you put them in the pan. Season with salt and pepper. Add 750 ml (3 cups) water and bring to the boil, then lower the heat, cover the pan and simmer gently for about 30 minutes. Remove from the heat and purée. The soup should be fairly thick: if it seems too watery, simmer uncovered for a while longer. If it seems too thick, add a little more water.

Check the seasoning and serve the soup hot with a dollop of yoghurt and a sprinkling of chopped olives, lemon rind and rosemary.