Lentil shepherd's pie is a vegetarian twist on a classic dish. Start by sautéing onions, garlic, and carrots in a pot until they are soft. Add in lentils, vegetable broth, and your favorite seasonings. Let the mixture simmer for about 20 minutes until the lentils are tender. Top with mashed potatoes and bake in the oven until the potatoes are golden brown. Serve for a delicious and comforting meal.