The Ultimate Moussaka

Trim and slice 3 pounds eggplants crosswise into 1/4-inch-thick rounds and place in a large bowl. Sprinkle with 3 1/2 teaspoons of the kosher salt and toss until combined. Transfer to a colander and set the colander over the bowl. Let drain for at least 30 minutes or up to 1 hour, tossing the eggplant halfway through. Meanwhile, arrange 2 racks to divide the oven into thirds and heat the oven to 425°F. Peel and cut 1 1/2 pounds Yukon gold potatoes into 1/4-inch-thick slices. Dice 1 large yellow onion and finely chop 8 garlic cloves. Pick the leaves from 2 fresh oregano sprigs and coarsely chop.

Rinse the eggplant, then squeeze and pat the slices dry with a clean kitchen towel or paper towels, removing as much moisture as possible. Arrange the slices in an even layer on 2 rimmed baking sheets and brush all over with 5 tablespoons of the olive oil.

Bake for 10 minutes. Rotate the baking sheets between racks and from front to back. Bake until the eggplant is golden-brown and tender, 10 to 15 minutes more. Meanwhile, brown the potatoes.

Heat 3 tablespoons of the olive oil in a large high-sided, heavy-bottomed skillet over medium heat until shimmering. Working in batches, add a single layer of sliced potatoes to the pan and cook, flipping halfway through, until golden-brown on both sides, 5 to 8 minutes per batch. Add more olive oil to the pan between batches as needed.

Arrange all of the cooked potatoes in an even layer a 9x13-inch baking dish. Sprinkle with 1/2 teaspoon of the kosher salt.

Return the skillet to medium-high heat. Add 2 pounds ground lamb and 1 teaspoon of the kosher salt. Cook, breaking up the lamb into small bits with a wooden spoon and stirring occasionally, until lamb is browned and cooked through, 8 to 10 minutes. Drain the excess fat from the skillet and transfer the lamb to a plate.

Return the skillet to medium-high heat and add the remaining 2 tablespoons olive oil. Add the onion and cook, stirring occasionally, until soft and light golden-brown, about 3 minutes. Add the garlic and cook, stirring often, until light golden and fragrant, about 2 minutes. Return the cooked lamb and any accumulated juices to the skillet. Add 2 tablespoons tomato paste, 1 tablespoon paprika, 3/4 teaspoon ground cinnamon, 1/4 teaspoon ground allspice, and 1/8 teaspoon cayenne. Cook, stirring constantly, for 1 minute.

Add 1 cup dry red wine and cook until mostly reduced, about 2 minutes. Add the oregano and 1 (28-ounce) can whole peeled tomatoes and their juices. Use a wooden spoon to break up the tomatoes into small pieces and bring to a boil. Reduce the heat to medium and simmer until thickened but still a bit saucy, about 15 minutes. Meanwhile, make the white sauce.

Melt 5 tablespoons unsalted butter in a medium saucepan over medium-high heat. Add 7 tablespoons all-purpose flour and cook, stirring constantly, until lightly toasted, about 1 minute. While whisking constantly, slowly pour in 5 cups whole milk and season with the remaining 1/2 teaspoon kosher salt. Bring to a simmer. Reduce the heat to maintain a simmer and cook, whisking constantly, until thickened to a thick, gravy-like consistency, about 10 minutes. Scrape the mixture into a large heatproof bowl and press a sheet of plastic wrap directly onto the surface to prevent a skin from forming. Let cool for 10 to 15 minutes.

When the lamb mixture is ready, taste and season with kosher salt and black pepper as needed. Remove the pan from the heat. When the white sauce is cooled slightly, uncover, add 3 large egg yolks and a pinch of ground nutmeg, and whisk to combine.

Reduce the oven temperature to 350°F. Arrange half of the eggplant slices in an even layer over the potatoes in the baking dish. Dollop the meat mixture on top and spread into an even layer. Layer the remaining eggplant slices over the meat mixture. Pour and spread the white sauce over the eggplant. Sprinkle with 6 ounces finely grated Pecorino Romano cheese (about 2 cups) and 1 cup panko breadcrumbs.

Bake until the top is golden brown in spots and the moussaka is warmed through and bubbling around the edges, 55 minutes to 1 hour. Let cool 15 minutes before slicing.