Super Veggie Lentil Taco “Meat”

Name: Super Veggie Lentil Taco “Meat”
Ingredients: 1 Tbs. olive oil, optional; 1 medium onion, diced (1 1/2 cups); 3 cloves garlic, minced (1 Tbs.); 1/2 large red bell pepper, chopped (1/2 cup); 3 oz. mushrooms, sliced (1 cup); 1 cup green or brown lentils, rinsed and drained; 1 medium carrot, sliced (1/2 cup); 2 ribs celery, sliced (1 cup); 1 1/2 Tbs. chili powder; 1 tsp. ground cumin; 1/2 tsp. smoked paprika; 1 tsp. dried oregano; 1 bay leaf; 1 dash cayenne pepper, optional; 2 cups low-sodium vegetable broth, plus more if needed; 1 Tbs. tomato paste; 1 Tbs. lime juice