Peel the beetroot then dice.
Cut the tomatoes in half, then place them in a roasting pan with the chopped garlic. Drizzle with half of the olive oil then bake at 190 degrees for 25-30 minutes until soft. Transfer the tomatoes & cooking juice into a blender and whizz until smooth. If you want it silky smooth, strain it through a sieve.
Meanwhile heat the remaining oil in a pan and gently cook the onion, then add the beetroot and stir for 5 minutes. Pour in the stock , season to taste, bring to the boil and simmer for about 10 minutes.
When the beetroot is soft, add the blended tomato and whiz with a hand-held mixer into a thick, smooth soup.
Reheat it to your liking. Serve with feta cheese crumbled on top, if you like.