Pour 1/2 cup (125 mL) boiling water over dried mushrooms. Soak for 15 minutes or until rehydrated. Drain and reserve mushroom liquid. Chop and set aside.
Meanwhile, heat oil in a large, heavy-bottom saucepan set over medium heat. Add onions, carrot, celery, fennel and garlic. Cook, stirring often, for 3 to 5 minutes or until softened.
Increase heat to medium-high; add mixed mushrooms, Italian seasoning, salt and pepper. Cook, stirring occasionally, for 6 to 8 minutes or until mushrooms are golden brown and tender. Stir tomato paste and rehydrated mushrooms. Cook for 2 minutes. Add red wine and stock and cook, scraping up any brown bits. Stir in reserved mushroom liquid, diced tomatoes, lentils and bay leaves; bring to a boil. Reduce heat to low. Simmer, stirring occasionally, for 30 minutes or until very thick and flavourful. Discard bay leaves.
During the last 20 minutes of simmering; cook pasta according to package directions and drain well, reserving 1/3 cup (75 mL) pasta water.
Toss spaghetti with sauce, reserved pasta water and parsley. Serve with Parmesan cheese.
Substitute chickpeas for the lentils, if desired. For non-vegetarians add sliced cooked chicken to sauce in last 10 minutes of cooking time.