Grill, bake or fry the sausages until cooked through. If using leftover cooked sausages, simply slice them ready for reheating.
Finely chop the onion, garlic, celery and carrot.
Heat the olive oil in a large frying pan or saucepan over a medium heat. Add the onion, celery and carrot and cook gently for about 8 minutes until softened.
Stir in the garlic and dried herbs and cook for 1 minute.
Add the chopped tomatoes and season with salt and pepper. Pour in a splash of water, cover and simmer for about 10 minutes, until the tomatoes have broken down into a thick sauce.
Stir in the kale and cook for another 5 minutes until just tender.
Add the lentils and warm through for 3–5 minutes.
Slice the sausages and stir them into the stew. Cook for a further 2–3 minutes until everything is piping hot.
Stir through the chopped parsley and serve immediately.