1. Prepare the Filling: In a large skillet, heat the olive oil over medium heat. Add the diced onion and garlic, sautéing until softened and fragrant.
2. Add the Vegetables: Add the diced carrots, celery, and mushrooms to the skillet, cooking until the vegetables are tender and caramelized.
3. Incorporate the Lentils: Stir in the drained lentils, frozen peas, tomato paste, soy sauce, dried thyme, and dried rosemary, ensuring all ingredients are well combined. Season with salt and pepper to taste.
4. Simmer and Thicken: Allow the filling to simmer for 10-15 minutes, allowing the flavors to meld together and the mixture to thicken slightly. Adjust seasoning if necessary.
5. Prepare the Mashed Potato Topping: While the filling simmers, place the chopped potatoes in a pot of boiling water and cook until tender. Drain the potatoes and return them to the pot.
6. Mash and Season: Using a potato masher or fork, mash the cooked potatoes until smooth and creamy. Stir in the unsweetened almond milk and vegan butter, continuing to mash until the desired consistency is reached. Season with salt and pepper to taste.
7. Assemble the Pie: Transfer the lentil and vegetable filling to a baking dish, spreading it out evenly. Carefully spread the mashed potato topping over the filling, smoothing it out with a spatula.
8. Bake to Perfection: Place the assembled pie in a preheated oven at 375°F (190°C) and bake for 25-30 minutes, or until the filling is bubbly and the mashed potato topping is golden brown and crispy.
9. Serve and Enjoy: Remove the Shepherd’s Pie from the oven and let it cool for a few minutes before serving. Garnish with fresh herbs if desired, then slice and serve piping hot.
