Heat the oil in a large saucepan and fry the onion, carrot and pepper for 5 minutes. Stir in the garlic, herbs, oats, mushrooms and Walnuts and fry for 1-2 minutes.
Stir in the tomatoes, lentils with the juice form the can and stock, bring to the boil, uncovered and simmer for 20 minutes. Sprinkle with parsley to garnish.
Cooks tip
Try using diced aubergine, sweet potato or squash or use a pouch of Puy lentils instead of the canned.