This lentil and mushroom shepherd's pie is a vegetarian twist on the classic comfort food. The lentils are cooked with onions, garlic, and mushrooms until they are tender and then topped with a layer of mashed potatoes. The result is a hearty and flavorful dish that is perfect for a cozy night in. The lentils provide a good source of protein and fiber, while the mushrooms add a meaty texture and umami flavor. This dish is also vegan and gluten-free, making it a great option for those with dietary restrictions.