Vegetarian Moussaka

Name: Vegetarian Moussaka
Ingredients: 1 eggplant, thinly sliced; 1 tablespoon olive oil; 1 lrg zucchini, thinly sliced; 2 potatoes, thinly sliced; 1 onion, sliced; 1 clove garlic, chopped; 1 tablespoon white vinegar; 1 (14.5 ounce) can whole peeled tomatoes, chopped; (14.5 ounce) can lentils, drained, juice reserved; 1 teaspoon dried oregano; 2 tablespoons chopped fresh parsley; salt and pepper to taste; 1 cup crumbled feta cheese; tablespoon butter; 2 tablespoons all-purpose flour; cup milk; black pepper to taste; 1 pch ground nutmeg; 1 egg, beaten; cup grated parmesan cheese