Take the cooked beetroot and blend in a food processor to a puree, adding the balsamic vinegar a drop at a time until the beetroot is nice and pureed but not too wet.
Lightly fry the onion in the olive oil until it is translucent then add the garlic and cook for 2 minutes.
Add the rice and stir until all of the grains have taken on the oil.
Add a ladle off the stock and stir over a medium heat until all of the stock has been absorbed and then add another ladle of stock. Keep repeating this process until the rice is nice and creamy but still firm. Keep tasting and checking the seasoning.
Once the rice has reached the right texture stir in the pureed beetroot and keep stirring for a further 2 minutes; again check the seasoning.