Process onion, carrot, celery and garlic in a food processor until finely chopped (or chop by hand).
Heat the oil in a saucepan over medium heat. Add onion mixture and bay leaves. Season. Cook, stirring, for 6 minutes or until soft.
Meanwhile, process mushrooms in food processor until finely chopped and add to the saucepan. Cook now all together, stirring, for 3 minutes or until soft.
Add rinsed lentils into mixture, stir in tomatoes, vegetable stock and passata.
Reduce heat to low. Cook, covered, stirring occasionally, for 25 minutes (or longer if time permits).
Season as desired. Continue to cook with lid off for a further 10-15 minutes to reduce sauce.
Cook up your pasta according to packet instructions.
Serve this sauce with your pasta and you can sprinkle a little feta cheese and fresh basil leaves on top (if you like!).
Enjoy your pasta with your non-starchy side salad or see our 'Sides' collection for other salad recipe option.