Preheat the oven to 190C/170 Fan/Gas 5.
Place the halved tomatoes in an ovenproof dish. Throw over the garlic and drizzle over half the olive oil.
Roast for 25-30 minutes in the oven until soft and pulpy. Rub through a sieve to remove the skin and pips.
Heat the remaining oil in a pan and sweat the onion for a few minutes until soft. Add the beetroot and the stock and bring to the boil. Season lightly with salt and freshly ground black pepper. Simmer gently for 7-10 minutes until the beetroot is tender.
Stir in the tomato purée, transfer the soup to a blender and process until completely smooth. Taste and adjust the seasoning if necessary
Divide between warm bowls and crumble over a little feta into each bowl. Serve with crusty bread.
