1. In a pot over medium-high heat, brown the onion, carrot, celery and garlic in 1 tbsp (15 ml) of the oil. Add the lentils and mix well. Add the broth, water, tomato paste, mustard and herbs. Bring to a boil. Cover and simmer over low heat for 40 minutes or until the lentils are tender. Remove and compost the thyme and bay leaf. Season with salt and pepper.
2. Meanwhile, in a large non-stick skillet over medium-high heat, brown the mushrooms in 2 tbsp (30 ml) of the oil. Season with salt and pepper. Set aside on a plate.
3. In the same skillet over medium-high heat, cook the Brussels sprouts in the remaining oil until al dente, about 2 to 3 minutes. Season with salt and pepper.
4. Add the mushrooms and Brussels sprouts to the pot of lentils. Cook for another 2 minutes while stirring. Add more broth as needed. Adjust the seasoning.
5. Serve the stew in shallow bowls. Top with the diced tomato and a drizzle of olive oil. Serve with slices of country bread, if desired.

NOTE FROM RICARDO

The stew can be prepared a day in advance and reheated the next day just before serving. Add broth to thin out the stew as needed.