Place prepared eggplant medallions in a bowl, and season liberally with salt. Separately, season potatoes in a bowl with salt, pepper, and garlic oil or extra-virgin olive oil. Set both aside for 1 hour.

Heat large sauté pan with oil until hot. Add onions and cook until translucent, stirring occasionally to prevent browning. Add garlic and stir for 30 seconds, being careful not to burn. Deglaze pan with red wine. Reduce red wine until fully absorbed by onions and garlic. Add ground meat, cooking until meat is thoroughly cooked. Drain meat mixture in colander or strainer. Discard reserve juices.

While meat mixture drains, add tomato paste to pan; cook for 1 to 2 minutes. Add drained meat mixture, mixing with spoon until tomato paste is incorporated. Season mixture with cinnamon, nutmeg, honey, salt, and pepper. Cook another 2 to 3 minutes. Set aside to let flavors marry.

Preheat oven to 350 degrees F.

After 1 hour, pat eggplant dry with paper towels; season with garlic, oil, salt, and pepper. Place both eggplant and potatoes on separate shallow pans; roast each until cooked and golden brown. When eggplant and potatoes are browned, begin layering the moussaka in a baking dish: potatoes on bottom, then meat mixture, followed by eggplant. Set dish aside.

Make béchamel. Melt butter in saucepan. Once melted, incorporate flour, stirring, until it forms a blond roux, 2 to 3 minutes. Add milk slowly, stirring constantly to avoid lumps. When sauce is smooth, turn heat to medium-high, and season with salt and pepper. Stir occasionally to avoid scorching. Thicken sauce, just below boil, for about 5 to 7 minutes. Once sauce is at desired consistency, remove from heat.

Fold in Greek yogurt, eggs, lemon juice, and nutmeg. Stir to incorporate; add salt and pepper, to taste.

Top prepared moussaka with béchamel, making sure béchamel covers dish. Bake for 30 to 45 minutes, until dark browning occurs over top. Let rest 15 to 20 minutes. Cut into 6 squares and serve.