The Ultimate Moussaka

Name: The Ultimate Moussaka
Ingredients: 3 large globe eggplants (about 3 pounds total); 5 1/2 teaspoons kosher salt, divided, plus more as needed; 1 1/2 pounds Yukon gold potatoes (5 to 6); 1 large yellow onion; 8 cloves garlic; 2 sprigs fresh oregano; 10 to 11 tablespoons olive oil, divided; 2 pounds ground lamb; 2 tablespoons tomato paste; 1 tablespoon paprika; 3/4 teaspoon ground cinnamon; 1/4 teaspoon ground allspice; 1/8 teaspoon cayenne pepper; Freshly ground black pepper; 1 cup dry red wine, such as Cabernet Sauvignon; 1 (28-ounce) can whole peeled tomatoes; 5 tablespoons unsalted butter; 7 tablespoons all-purpose flour; 5 cups whole milk; 3 large egg yolks; Pinch ground nutmeg; 6 ounces finely grated Pecorino Romano or Parmesan cheese (about 2 cups); 1 cup panko breadcrumbs