Vegetable Shepherd’s Pie

Ingredients

  • 3 lb. russet potatoes, unpeeled

  • 3 lbs. Yukon Gold potatoes, unpeeled

  • ½ c. (1 stick) unsalted butter, cubbed

  • Kosher salt

  • ¾ c. brown or green lentils

  • 6 garlic cloves, divided, plus 2 tbsp. chopped garlic

  • 1 tsp. kosher salt plus more for seasoning

  • 5 tbsp. olive oil, divided

  • 3 c. coarsely chopped onions

  • 2 tbsp. tomato paste

  • 2 bay leaves

  • 2 c. dry white wine

  • 8 c. vegetable broth

  • 2 tbsp. cornstarch

  • 2 tbsp. gluten-free white miso or 2 tsp. gluten-free tamari soy sauce

  • Freshly ground black pepper

  • 12 c. ½-inch pieces peeled vegetables (such as squash, turnips, carrots, and parsnips)

  • 1 c. frozen pearl onions, thawed, halved

  • 2 4-inch sprigs rosemary

  • 2 c. bite-size pieces mixed fresh mushrooms

  • ¼ c. chopped mixed fresh herbs (such as parsley, chives, and sage)

Instructions

  1. Preheat oven to 450°. Bake potatoes on a foil-lined baking sheet until tender, about 45 minutes. Let cool slightly, then peel. Press potatoes through a ricer, food mill, or colander into a large bowl. Add butter; stir until well blended. Stir in milk. Season to taste with salt.

  2. Soak dried porcini in 3 cups hot water; set aside. Combine lentils, 1 garlic clove, 1 tsp. salt, and 4 cups water in a medium saucepan. Bring to a boil; reduce heat and simmer, stirring occasionally, until lentils are tender but not mushy, 15–20 minutes. Drain lentils and discard garlic.

  3. Heat 3 Tbsp. oil in a large heavy pot over medium heat. Add onions and cook, stirring occasionally, until soft, about 12 minutes. Add chopped garlic and cook for 1 minute. Stir in tomato paste. Cook, stirring constantly, until tomato paste is caramelized, 2–3 minutes.

  4. Add bay leaves and wine; stir, scraping up any browned bits. Bring to a simmer and cook until liquid is reduced by half, about 10 minutes. Stir in broth and cook, stirring occasionally, until reduced by half, about 45 minutes.

  5. Strain mixture into a large saucepan and bring to a boil; discard solids in strainer. Stir cornstarch and 2 Tbsp. water in a small bowl to dissolve. Add cornstarch mixture; simmer until thickened, about 5 minutes. Whisk in miso. Season sauce with salt and pepper. Set aside.

  6. Preheat oven to 450°. Toss vegetables and pearl onions with remaining 2 Tbsp. oil, 5 garlic cloves, and rosemary sprigs in a large bowl; season with salt and pepper. Divide between 2 rimmed baking sheets. Roast, stirring once, until tender, 20–25 minutes. Transfer garlic cloves to a small bowl; mash well with a fork and stir into sauce. Discard rosemary. 

  7. Arrange lentils in an even layer in a 3-qt. baking dish; set dish on a foil-lined rimmed baking sheet. Toss roasted vegetables with fresh mushrooms and chopped herbs; layer on top of lentils. Pour sauce over vegetables. Spoon potato mixture evenly over.

  8. Bake until browned and bubbly, about 30 minutes. Let stand for 15 minutes before serving.