• 80 g (2 ½ oz) butter
• 1 large onion, finely diced
• 1 teaspoon cumin seeds
• 12 sage leaves, torn in half
• 1 medium leek, washed and finely sliced
• 2 cloves garlic, peeled and sliced
• 1 large orange kumara, about 400 g/14 oz, peeled and cut into 1 cm (½ in) cubes
• ¼ cup split red lentils, rinsed
• 1 litre (2 pints) vegetable stock or water
• 3 tablespoons olive oil
• 1 large red onion, finely sliced
• 1 tablespoons balsamic vinegar
• 1 large handful chopped parsley

Melt butter in a deepish saucepan over a high heat until nut-brown and foamy. Add onion and cumin seeds. Cook 2–3 minutes, stirring to prevent burning. Add sage, leek, garlic and kumara and stir well. Add lentils and stock and bring to the boil. Simmer 30 minutes until lentils and kumara are tender.

While soup is cooking, heat oil in a small frying pan, add red onion and cook over a moderate heat, stirring occasionally, until it begins to caramelise. Add vinegar, cook until it has evaporated, then remove from heat.

Adjust soup for seasoning and stir in parsley. Ladle into bowls and dollop the onions on top.