Harvest Vegetable Casserole with Lentils and Gravy

Ingredients

• 3 cups cooked brown lentils (2 15-oz. cans)
• 4 cups vegetable broth, divided
• 1 medium cauliflower, cut into 3-inch florets
• 1 medium acorn squash, unpeeled, cut into 3-inch pieces
• 4 carrots, peeled and cut into 3-inch pieces
• 1 cup fresh or frozen pearl onions, peeled if fresh (about 20)
• 24 oz. cremini mushrooms, cut into halves (divided)
• ½ medium onion, cut into ¼-inch dice (1 cup)
• 15 garlic cloves, minced (about 2½ tablespoons)
• 1 3-inch cinnamon stick
• 4 dried bay leaves
• 3 tablespoons oat flour or whole wheat flour
• 3 tablespoons tomato paste
• ¼ cup reduced-sodium tamari or soy sauce
• ¼ cup lemon juice
• ¼ cup finely chopped fresh parsley, divided
• 2½ tablespoons finely chopped fresh thyme leaves
• 2½ tablespoons finely chopped fresh sage leaves
• 2 tablespoons pine nuts
• 2 tablespoons dried cranberries, chopped