Phase 1: Prepare the Eggplant (The Foundation)

1. Slice and Salt: Wash and trim the eggplants. Slice them lengthwise into ⅓-inch thick planks. Arrange the slices in a single layer on baking sheets or in a large colander. Sprinkle them generously on both sides with coarse salt.

2. Let it Sweat: Let the salted eggplant sit for 30-60 minutes. You will see beads of water form on the surface. This process draws out the bitter liquid and ensures the eggplant won’t be watery.

3. Rinse and Dry: Thoroughly rinse the eggplant slices under cold water to remove all the salt. Then, pat them completely dry with paper towels or a clean kitchen towel. This drying step is crucial for getting a good roast.

4. Roast the Eggplant: Preheat your oven to 400°F (200°C). Brush both sides of the dry eggplant slices lightly with olive oil and arrange them in a single layer on parchment-lined baking sheets. Roast for 15-20 minutes, flipping once halfway through, until they are tender and lightly browned. Set aside.

Phase 2: Make the Rich Meat Sauce

1. Sauté Aromatics: In a large Dutch oven or heavy-bottomed pot, heat 2 tablespoons of olive oil over medium-high heat. Add the chopped onions and cook for 5-7 minutes until softened. Add the minced garlic and cook for another minute until fragrant.

2. Brown the Meat: Add the ground lamb to the pot. Break it up with a spoon and cook until it is browned all over. Drain off any excess fat.

3. Deglaze and Simmer: Pour in the ½ cup of red wine to deglaze the pan, scraping up any browned bits from the bottom. Let it bubble and reduce for a couple of minutes. Stir in the tomato paste, crushed tomatoes, cinnamon, allspice, oregano, bay leaf, and optional sugar. Season with salt and pepper.

4. Develop Flavors: Bring the sauce to a simmer, then reduce the heat to low, cover, and let it cook for at least 30-45 minutes (or up to an hour) for the flavors to meld and the sauce to thicken. Remove the bay leaf before assembling.

Phase 3: Create the Velvety Béchamel Sauce

1. Warm the Milk: Gently warm the 4 cups of milk in a saucepan or in the microwave. Warm milk incorporates into the roux more easily and helps prevent lumps.

2. Make the Roux: In a separate, medium-sized saucepan, melt the ½ cup of butter over medium heat. Whisk in the ½ cup of flour and cook, whisking constantly, for 1-2 minutes. This cooks out the raw flour taste.

3. Build the Sauce: Gradually pour the warm milk into the roux, whisking vigorously and constantly to prevent lumps. Add about one cup at a time, whisking until smooth before adding more. Once all the milk is incorporated, bring the sauce to a gentle simmer and cook, stirring frequently, for 5-8 minutes until it is very thick (it should coat the back of a spoon heavily).

4. Temper the Eggs (The Secret Step): Remove the saucepan from the heat. In a separate small bowl, lightly beat the 2 egg yolks. Slowly ladle about a cup of the hot béchamel sauce into the egg yolks, whisking the yolks constantly. This gently raises their temperature without scrambling them.

5. Finish the Sauce: Pour the tempered egg yolk mixture back into the saucepan with the rest of the béchamel, whisking to combine. Stir in ¾ cup of the grated cheese, the nutmeg, and season with salt and white pepper. The sauce should be very thick and creamy.

Phase 4: Assemble and Bake

1. Preheat and Prepare: Keep your oven at 375°F (190°C).

2. First Layer: Arrange half of the roasted eggplant slices in the bottom of your 9×13 inch baking dish, overlapping them slightly to create a solid base.

3. Meat Layer: Spoon the entire meat sauce mixture evenly over the eggplant layer.

4. Second Eggplant Layer: Arrange the remaining eggplant slices over the meat sauce.

5. The Crowning Glory: Pour the thick béchamel sauce over the top layer of eggplant and spread it evenly to cover the entire surface. Sprinkle the remaining ¼ cup of grated cheese over the top.

6. Bake: Place the dish on a baking sheet (to catch any potential drips) and bake for 40-50 minutes, or until the top is beautifully golden brown and bubbly.

7. REST THE MOUSSAKA: This is the most critical final step. Let the moussaka rest on a wire rack for at least 30 minutes before attempting to slice and serve. This allows the layers to set.