Snap the bottom ends of the celery and lift up to remove the strings, then finely chop. Heat the oil in a large saucepan, then add the celery, potatoes, carrots, leek, garlic and onions. Cook gently for 10-15 mins, until the vegetables have softened slightly.

Add the stock, then stir in the lentils and curry powder. Bring to a boil, then reduce to a medium heat and simmer for 30 mins, until the lentils are tender. Taste and season with the red wine vinegar, a little salt and pepper and a pinch of sugar. Sprinkle over the parsley to serve. This recipe has been provided by Einfach Backen and not been re-tested by us.