Easy Lentil Shepherd's Pie (vegetarian)

Name: Easy Lentil Shepherd's Pie (vegetarian)
Prep time: 20 min
Cook time: 1 h
Total time: 1 h 20 min
Cuisine: American, British
Ingredients: 1 cup brown lentils (or green lentils); 3-4 cups vegetable broth (or beef broth if not making vegetarian); 2 teaspoons olive oil; ½ cup onion (chopped); 1 cup chopped mushrooms (about 4 oz); 1 carrot (chopped); 1 rib celery (chopped); ½ cup frozen peas (defrosted); ½ tablespoon flour; 3 tablespoons red wine; 2 teaspoons Worcestershire sauce ((use vegetarian Worcestershire sauce if desired)); 3 tablespoons tomato paste; 2 tablespoons parsley (chopped); salt & pepper to taste; 2 ½ cups prepared mashed potatoes