Cut the eggplant in half, then score the cut side with a sharp paring knife without breaking the skin at the edges. Heat a large skillet over high heat. Swirl in 2 tablespoons of the olive oil , then add two eggplant halves, cut side down. Sear for 1 minute without disturbing, then add 3 tablespoons water. Cover and reduce the heat to low. Steam the eggplant halves for 10 minutes. Set the halves aside to cool on a large platter and repeat with the remaining halves.
After the eggplant has cooled enough that you can handle it, scrape the pulp into a large bowl using a teaspoon, taking care not to break the skin. You should have 4 cups eggplant pulp. Reserve the skins, discarding any additional pulp.
Heat a large skillet or saute pan over medium heat. Swirl in the remaining 2 tablespoons olive oil , then add the onion and cook until soft and fragrant, about 2 minutes, stirring frequently. Stir in the garlic. Cook for 30 seconds. Add the ground lamb and cook until lightly browned, about 2 minutes, stirring constantly.
Add the reserved 4 cups eggplant pulp and the sweet vermouth . Mix well with a wooden spoon, then stir in the cinnamon , salt , cumin, and pepper . Continue cooking until the eggplant gives off its liquid and begins to coat the pan with a fine film, about 5 minutes, stirring constantly. Set aside to cool for at least 30 minutes. (The eggplant filling can be made up to this point a day in advance; cover tightly when cooled and refrigerate, then allow to come back to room temperature before proceeding.)
Peel the potatoes and cut them in half. Beginning with the cut side, cut off thin slices, using a sharp knife or a sturdy vegetable peeler. (You don't want paper-thin slices; make them about the thickness of lasagna noodles.) Place the potato slices in a large bowl of water as you work.
Bring a medium pot of salted water to a boil. Drain the potato slices and add them to the pot. Cook just until crisp, about 3 minutes. Drain -- be careful, for they are fragile -- and set aside.
Mix the eggs into the eggplant pulp mixture. Position the rack in the center of the oven and preheat the oven to 350 degrees F. Oil a 2-quart high-sided souffle dish with olive oil .
Place the eggplant skins in the souffle dish, skin side out, so that they meet and overlap on the bottom, then rise up along the insides of the dish. In other words, the eggplant skins should form a kind of "skin" around the moussaka as it bakes. Overlap them as necessary. If any tear, plug the hole with a small amount of the eggplant pulp mixture. Let the skins hang over the top of the souffle dish.
Lay one-fifth of the potato slices on top of the eggplant skins on the bottom of the dish. Top with 1 cup eggplant pulp mixture. Build three more layers, then top with a final layer of potato slices. Fold the eggplant skins over to seal the dish. If the skins don't meet, it doesn't matter.
Oil a 10-inch-long piece of foil. Place it, oiled side down, over the casserole and loosely seal it. Bake the moussaka for 1 hour 30 minutes. Cool on a wire rack for 10 minutes, then serve.
Cheesy Potato Moussaka : Layer 2 tablespoons grated Manchego or other sheep's milk cheese on top of each layer of potatoes (you'll need 1/2 cup plus 2 tablespoons or about 3 ounces).
Lebanese Moussaka : Stir 1/2 cup raisins and 1/2 cup slivered almonds into the eggplant mixture. Each layer of eggplant pulp mixture in the casserole will be 1-1/4 cups, rather than 1 cup.
Vegetarian Moussaka : Omit the ground lamb. Stir 2 cups cooked kasha into the eggplant pulp mixture.
Yield: 6 servings Source: The Ultimate Potato Book by Bruce Weinstein and Mark Scarbrough (Wm Morrow)
Reprinted with permission.