Heat the oil in a saucepan over a medium low heat. Add the onions and cook gently, for 15-20 minutes or until well browned. Stir in the garlic, ginger and spices and cook for 1 minute until fragrant.

Add the split peas, vegetables, stock and water to the saucepan. Bring to the boil, reduce heat and simmer covered, for 50 minutes stirring occasionally until the peas have broken down and the soup is thick. Remove from heat and stir in milk.

Combine yoghurt and mint in a small bowl. Ladle the soup into serving bowls and top each with a swirl of minted yogurt.

Serve soup with wholegrain bread and wedges of lemon, if desired.