1. Heat the olive oil in a large saucepan or oven proof casserole dish over a medium heat and fry the onion for 5 minutes until soft
2. Add the garlic, mushrooms and oregano and fry for a further 3 minutes
3. Add the passata and lentils and stir together
4. Add the hot vegetable stock, Worcestershire sauce, and most of the fresh basil, stir and season with salt and pepper. Reduce the heat and simmer over low heat for 30 minutes, stirring occasionally. Alternatively, cook in the oven at 180°C/360°F/gas mark 4 for 30 minutes