Heat some olive oil on a medium heat in a large saucepan.

Cook the onion and garlic for one minute.

Add the carrots, celery and mushrooms alongside a good pinch of salt. Cook for five minutes.

Add the stock, lentils, herbs, tomato purée, seaweed, vinegar and tamari. Give it a good stir.

Cook for about 20 minutes on a low heat until the lentils are cooked through.

While the stew is cooking, boil the sweet potatoes in a large pan of water for about 20 minutes until tender.

Mash with salt and pepper, and olive oil.

Add some chopped chives for extra flavour.

Stir the spinach through the stew and serve with a dollop of mash.

Garnish with fresh parsley.

Hearty stew with sweet potato mash recipe: the perfect work lunch to keep you energised all afternoon