Versatile Moussaka

Name: Versatile Moussaka
Ingredients: 2 pound eggplants, cut crosswise into 1/4 slices; 2 large russet potatoes, peeled and cut crosswise into 1/4 slices; 1/4 cup dried currants; 1 pound ground lamb or beef; 1 medium onion, small dice; 6 cloves garlic, minced; 1 1/2 teaspoon ground cinnamon; 1 teaspoon cayenne; 1/2 teaspoon ground ginger; 1/4 teaspoon ground cloves; 1/4 teaspoon ground allspice; 1 bay leaf; 1/4 cup tomato paste (optional); 1 cup red wine (I used Syrah, feel free to play around); 1 28-oz. can whole peeled tomatoes in juice, crushed; Kosher salt and freshly ground black pepper, to taste; 6 tablespoon unsalted butter; 1/2 cup flour; 2 cup milk; Ground nutmeg, to taste; 1/2 cup plain Greek yogurt; 2 eggs; 1 cup grated Parmesan or Gruyere