Vegetarian Moussaka

Name: Vegetarian Moussaka
Ingredients: For the Vegetables:; 1 1/2 pounds eggplant (2 to 3 eggplants, cut lengthwise into 1/4-inch slices); 1 1/2 pounds zucchini (cut lengthwise into 1/4-inch slices); Kosher salt, to taste; 1 1/4 pounds potatoes; 4 egg whites (reserving the yolks for béchamel); 2 cups breadcrumbs; For the Tomato Sauce:; 2 tablespoons olive oil; 1 medium onion (diced); 2 garlic cloves (minced); 1 (15 ounces) can chickpeas (drained, rinsed, and mashed); 1 (15 ounces) can diced tomatoes (with liquid); 2 tablespoons tomato paste; 1/4 teaspoon cinnamon (ground); 1 teaspoon oregano (dried); 1/2 teaspoon cumin (ground); 1 teaspoon sugar; Salt and pepper, to taste; For the Béchamel Sauce:; 1/2 cup unsalted butter (1 stick); 1/2 cup all-purpose flour; 3 cups milk (warmed); 4 egg yolks (beaten); A pinch of ground nutmeg; For Assembly:; 3 tablespoons breadcrumbs; 3/4 cup grated Kefalotyri (or Parmesan cheese)