Peel and chop the onions. Clean, wash and cut the celery into small cubes
Heat the oil in a large frying pan and fry the minced meat until crumbly. Finally add onions, fry briefly and season with salt, pepper and thyme. Add red wine and stock. Add celery, tomato paste and bay leaf. Bring to the boil, cover and stew for 8-10 minutes
Place spaghetti in plenty of boiling salted water and cook according to package instructions
Cut the beetroot into cubes, add to the bolognese and braise for another 2 minutes. Season to taste with salt and pepper. Drain spaghetti, arrange on deep plates with the bolognese and crumble feta cheese over it