• Step 1: Preheat your oven to 375°F (190°C). Arrange the eggplant slices on a baking sheet, brush them with olive oil, and season with salt and pepper. Bake for 15-20 minutes, or until the eggplant is softened and lightly browned. Remove from the oven and set aside.
• Step 2: In a large skillet, cook the ground beef or lamb over medium-high heat, breaking it up with a wooden spoon, until browned and cooked through, about 5-7 minutes. Drain any excess fat from the pan.
• Step 3: Add the diced onion and minced garlic to the skillet and cook for an additional 3-4 minutes, until the onion is translucent.
• Step 4: Stir in the diced tomatoes, tomato paste, cinnamon, and oregano. Season with salt and pepper to taste. Simmer the meat mixture for 10-15 minutes, allowing the flavors to meld.
• Step 5: In a separate saucepan, melt the butter over medium heat. Whisk in the flour and cook for 2-3 minutes, stirring constantly, to create a roux. Gradually whisk in the milk and continue cooking until the sauce thickens, about 5-7 minutes. Remove from heat and stir in the Parmesan cheese and beaten eggs.
• Step 6: Grease a 9×13-inch baking dish. Layer half of the roasted eggplant slices in the bottom of the dish. Top with the seasoned ground meat mixture, then the remaining eggplant slices. Pour the béchamel sauce over the top, ensuring it covers the entire surface.
• Step 7: Bake the moussaka for 45-55 minutes, or until the top is golden brown and the sauce is bubbling. Allow the moussaka to rest for 15-20 minutes before serving.