Shepherd's Pie with Vegetables

First, peel the potatoes and sweet potato, place them in a large pot, cover with enough water, and bring to a boil over high heat. Meanwhile, peel the onion and garlic, finely chop the onion, and press the garlic. Once the water in the pot starts boiling, reduce the heat to medium and cook the potatoes and sweet potato until tender for 15–20 minutes.

Meanwhile, clean the mushrooms and cut them into small pieces (roughly the size of beans). Drain the red beans and lentils and rinse them under running water.

Once the potatoes and sweet potato are cooked, drain the contents of the pot, add milk and salt, and mash everything into a smooth purée.