Preheat your oven to 375°F (190°C). Arrange the eggplant slices in a single layer on baking sheets lined with parchment paper. Lightly coat the eggplant with cooking spray and season with salt and pepper. Bake for 25 minutes, flipping halfway through, until the eggplant is tender and golden. Set aside.

In a large skillet over medium heat, cook the ground meat, breaking it apart with a spoon, until browned. Add the onion and garlic, and cook until softened about 5 minutes.

Stir in the crushed tomatoes, oregano, cinnamon, allspice, salt, and pepper. Reduce the heat to low and simmer the sauce for 15 minutes, allowing the flavours to meld.

While the sauce simmers, prepare the béchamel. In a saucepan over medium heat, whisk the flour and a small amount of milk until smooth. Gradually add the remaining milk, whisking constantly to prevent lumps. Cook until the mixture thickens, about 10 minutes. Remove from heat, and stir in nutmeg and half of the Parmesan cheese. Allow the sauce to cool slightly before whisking in the beaten egg whites.

To assemble the moussaka, lightly coat a baking dish with cooking spray. Layer half of the eggplant slices on the bottom, followed by the meat sauce. Repeat with the remaining eggplant and sauce. Pour the béchamel over the top and sprinkle with the remaining Parmesan cheese.

Bake for 40 minutes or until the top is golden and the moussaka is bubbling. Let it rest for 10 minutes before serving.

Prep: 20 minutes | Cook: 1 hour | Total: 1 hour 20 minutes

Servings: 6Cooking Time: 1 hourTotal Time: 1 hour 20 minutesKcal: Approximately 300 kcal per serving