Cook the lentils: In a medium saucepan, combine the lentils and vegetable broth (or water). Bring to a boil, reduce the heat, and simmer for 20-25 minutes until the lentils are tender but not mushy. Drain any excess liquid and set aside.

Prepare the filling: In a large skillet, heat olive oil over medium heat. Add onion, garlic, carrots, and celery. Sauté for 5-7 minutes until softened. Add mushrooms and cook for another 4-5 minutes until slightly browned. Stir in tomato paste, soy sauce, thyme, smoked paprika, and cumin. Cook for 2 minutes. Add cooked lentils and peas, stir to combine, and season with salt and pepper to taste.

Make the mashed potatoes: Boil the potatoes in salted water for 15-20 minutes until tender. Drain and return to the pot. Add plant-based milk and vegan butter, then mash until smooth. Season with salt and pepper to taste.

Assemble the Shepherd’s Pie: Preheat your oven to 400°F (200°C). Spread the lentil filling in a large baking dish. Spoon the mashed potatoes on top and create ridges with a fork if desired.

Bake: Bake for 20-25 minutes until the top is lightly golden and slightly crispy.

Garnish and serve: Let cool for a few minutes, garnish with parsley, and serve hot.