Sauté Aromatics: Heat the olive oil in a large, oven-safe skillet over medium heat until shimmering. Add the chopped onions along with a pinch of salt and cook for 8–10 minutes, stirring occasionally, until the onions develop a deep golden-brown color. This slow caramelization builds rich flavor. Next, stir in the minced garlic, thyme, and rosemary. Cook for another 2 minutes, stirring frequently, until fragrant.
Develop the Base: Push the onions to the edges of the pan, creating a space in the center. Add the tomato paste into this space and cook for 2–3 minutes, stirring occasionally, until it darkens and intensifies in flavor. Lower the heat if needed to prevent burning.
Deglaze with Wine: Pour in the red wine and use a wooden spoon to scrape up any browned bits from the bottom of the pan. Let the wine simmer gently for about 3–4 minutes until it reduces almost completely and the alcohol aroma fades.
Simmer Lentils: Add the vegetable broth, lentils, bay leaves, and paprika to the skillet. Stir everything to combine, then increase the heat to bring the mixture to a boil. Once boiling, reduce to a steady simmer and cook uncovered for 25–30 minutes, or until the lentils are tender and most of the liquid is absorbed.
Season and Enrich: Lower the heat to low. Stir in the tahini, tamari, balsamic vinegar, and vegan Worcestershire sauce if using. Taste and adjust seasoning with salt and pepper. Keep warm while preparing the topping.
Prepare Vegetables for Topping: Peel the potatoes and cut them into eighths. Place potatoes and cauliflower florets in a large pot, cover with water, and add the kosher salt and rosemary sprig. Bring to a boil and cook for approximately 15 minutes or until both vegetables are very tender.
Drain and Dry: Drain the cooked vegetables thoroughly in a colander. Remove and discard the rosemary sprig. For best texture, pat the potatoes dry with a clean towel and squeeze excess water from the cauliflower to avoid watery mash.
Mash the Topping: Return the potatoes and cauliflower to the pot or a large bowl. Add the vegan butter, coconut milk, nutritional yeast, and season with salt and pepper. Mash using a handheld masher or blend with an immersion blender until smooth and creamy. Taste and adjust salt as needed.
Assemble the Pie: Preheat your oven to 375°F (190°C). If using an ovenproof skillet, keep the lentil filling in it; otherwise, transfer the lentils to a baking dish (about 3 quarts/liters). Spread the mashed vegetable topping evenly over the lentil layer. Drizzle with olive oil and sprinkle with flaky salt, pepper, and fresh thyme leaves for added flavor.
Bake and Broil: Bake for 20 minutes until the filling bubbles at the edges. Then switch your oven to broil and place the pie under the broiler for a few minutes until the topping develops a golden crust. Watch closely to avoid burning.
Rest and Serve: Let the pie rest for 20 minutes to firm up before serving. Garnish with fresh parsley and an extra drizzle of olive oil if desired. Store leftovers in an airtight container in the fridge for up to four days.
