Next, toss in the minced garlic, diced carrots, and sliced mushrooms, stirring and cooking for another 5-7 minutes until the mushrooms start to soften and the mixture becomes aromatic.
Add the rinsed lentils to the pot, followed by the vegetable broth, tomato paste, thyme, rosemary, salt, and pepper. Bring this heavenly mix to a boil, then reduce it to a gentle simmer.
Let it cook for about 25-30 minutes, or until the lentils are tender and the mixture is thickened. Stir occasionally to prevent sticking.
While the lentil filling is simmering, prepare your mashed potatoes. In a separate pot, boil the diced Russet potatoes in salted water until fork-tender, usually about 15-20 minutes.
Once they are ready, drain the potatoes and return them to the pot.
Add the plant-based milk, vegan butter (or regular butter if that’s your preference), and season with salt and a pinch of nutmeg. Mash until creamy and smooth, leaving little peaks for extra fluffiness.
Preheat your oven to 400°F (200°C). Spread the lentil and mushroom filling evenly in a large baking dish. Layer the creamy mashed potatoes on top, spreading them evenly to cover the filling completely.
Use a fork to create some patterns on the surface. Place the baking dish in the preheated oven and bake for 25-30 minutes, or until the top is golden brown and crispy.
Let it cool slightly before serving to allow the flavors to meld beautifully.
Notes
Leftovers can be stored in an airtight container in the fridge for up to 4 days. Can be frozen for up to 3 months.