Vegetable Moussaka

Name: Vegetable Moussaka
Ingredients: pound eggplant unpeeled, and; cut into 1/2-thick rounds; Salt as needed; cup olive oil - (about); 1 lrg onion thinly sliced; 1 cup finely-chopped peeled carrots; 1 cup finely-chopped celery; 4 garlic cloves minced; 12 ounces portobello mushrooms cut ½ pieces; 1 teaspoon dried oregano; teaspoon ground cinnamon; 1 can crushed tomatoes with added puree (28 oz); cup chopped fresh Italian parsley; Salt to taste; Freshly-ground black pepper to taste; 1 cup grated Parmesan cheese; 6 tablespoons butter - (¾ stick); 7 tablespoons all-purpose flour; cup whole milk; 4 lrgs egg yolks