Begin by slicing the eggplants, potatoes, and zucchini into ¼-inch rounds. Sprinkle salt over the eggplant slices and let them sit for 30 minutes to draw out moisture and bitterness. Afterward, pat the eggplant dry with paper towels.

In a large skillet, heat olive oil over medium heat. Fry the salted eggplant slices until golden brown, about 3-4 minutes per side. Set aside on a plate lined with paper towels. Repeat with zucchini and potato slices.

In a large pot, heat a tablespoon of olive oil and sauté chopped red onions until they soften, around 5 minutes. Add minced garlic and ground meat, cooking until the meat is fully browned.

Pour in red wine, letting it simmer until mostly evaporated, about 3-5 minutes. Add canned crushed tomatoes, cinnamon, nutmeg, white pepper, oregano, and thyme. Let sauce simmer for 10-15 minutes.

In a separate saucepan, melt butter over medium heat. Whisk in flour to create a roux, stirring constantly for about 2 minutes. Gradually whisk in milk, stirring until thickened, around 5-7 minutes. Incorporate egg yolks and grated cheese.

In a greased baking dish, layer the components: first, potato slices, then fried eggplant, followed by zucchini. Spread half of the meat sauce, then repeat with another layer of vegetables and remaining meat sauce. Top with béchamel.

Preheat oven to 350°F (175°C). Bake the assembled moussaka for 40-45 minutes, or until the top is golden brown and bubbling. Allow to rest for 30 minutes before slicing.