1. Cover potatoes with water in a large saucepan. Add 1 tablespoon salt, bring to a simmer over medium-high heat, and cook until potatoes are tender, 8 to 10 minutes.
2. Drain potatoes and return to the now-empty saucepan. Using a potato masher, mash potatoes until smooth, then stir in almond milk, ¼ cup oil, and chives. Season with salt and pepper to taste; cover and set aside.
3. Heat the remaining 1 tablespoon oil in a broiler-safe 10-inch skillet over medium heat until shimmering. Add onion, mushrooms, and ¼ teaspoon pepper and cook until softened, about 5 minutes. Stir in tomato paste and garlic and cook until the bottom of the skillet is dark brown, about 2 minutes.
4. Stir in Madeira and cook, scraping up any browned bits, until evaporated, about 1 minute. Stir in flour and cook for 1 minute. Stir in broth, carrots, Worcestershire, thyme sprigs, and bay leaf and bring to a boil, scraping up any browned bits. Reduce heat to medium-low and simmer gently until carrots and mushrooms are tender, 10 to 15 minutes. Discard thyme sprigs and bay leaf, stir in protein crumbles, and season with salt and pepper to taste.
5. Adjust the oven rack 5 inches from the broiler element and heat the broiler. Transfer mashed potatoes to a 1-gallon zipper-lock bag, seal the top, and snip off the bottom corner to make a 1-inch opening. Pipe potatoes evenly over the filling to cover. Smooth potatoes with the back of a spoon, then make ridges over the surface with a fork. Place the skillet on a rimmed baking sheet and broil until potatoes are golden and crusty, 5 to 10 minutes. Let cool for 10 minutes before serving.

With permission from and thanks to Vegan for Everybody (p. 199). America's Test Kitchen. Photo by ATK.

‍