Vegetarian Shepherd’s Pie Recipe

• In a large pot, bring a gallon of water and 2 tablespoons salt to a boil over high heat.
• Add potatoes to boiling water and boil for about 15 to 20 minutes, until soft; a knife should go in with almost no resistance.
• Meanwhile, prepare the filling: In a 10-inch oven-safe skillet with high sides or an enameled cast-iron braiser over medium-high heat, bring the lentils, thyme and 2 cups of the broth to a simmer with 1 teaspoon salt.
• Reduce the heat and continue to cook the lentils, partly covered, until they are tender and most of the liquid is absorbed, about 20 minutes. Transfer the lentils to a bowl.

Finish the topping:

• In a small saucepan or a microwave oven, heat 6 tablespoons of the butter and milk together until butter melts. Drain potatoes well and return to pot. Using a masher or a ricer, mash hot potatoes until smooth. Mix in the hot butter mixture and sour cream just until blended. Stir in 1/2 of the Parmigiano. Season to taste with salt and pepper. Cover and set aside.

Finish the filling:

• Heat the oven to 375 degrees. Melt the butter in the 10-inch skillet over medium-high heat. Add the mushrooms and cook, stirring often with a wooden spoon, until they are deep golden brown, about 8 to 10 minutes.
• Reduce the heat to medium and add leeks, carrots and garlic, and continue to cook until tender, another 10 minutes. Season to taste with salt and pepper.
• Add the tomato paste and stir, cooking until it is well combined, another 2 to 3 minutes. Sprinkle flour over the mixture, stir and cook for 1 minute. Add remaining 1 1/2 cups broth, cooked lentils and peas, and cook until thickened. Remove thyme stems and stir in lemon juice to taste.
• Top the mixture with dollops of the mashed potatoes, then spread them out over the top. (Or transfer the lentil mixture to a 3-quart casserole dish and spread into an even layer, and top with potatoes.)
• Sprinkle with the remaining Parmigiano. Transfer to the oven and, if the mixture is at the top edges of your pan, set a foil-lined baking sheet underneath the pan to catch any drips.
• Bake the pie until the potatoes have begun to brown and the edges are bubbling, about 30 minutes.
• Let stand at room temperature for 15 minutes before serving.