Peel the beetroot then roughly dice.
Heat the oil in a saucepan, and gently fry the onion, garlic and cumin for 5 minutes.
When the onion is soft, add the beetroot and pour in the stock. Bring to the boil and simmer over low heat for 30 minutes, under cover.
Meanwhile, prepare the spiced yogurt: dry-fry the cumin and coriander seed until fragrant, then using a pestle & mortar grind them into a powder. Add the paprika and cayenne.
Mix 1 tsp of the space mixture with the yoghurt (keep the rest for later servings).
When the beetroot is tender, liquidize the soup or, using a stick-blender, whiz until smooth. Season with salt and pepper to your liking.
Ladle the soup into bowls, add a dollop of the spiced yogurt and top with some chopped parsley. Serve with wholesome bread.