- 1 eggplant, thinly sliced
- 1 tablespoon olive oil, or more as needed
- 1 large 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
- 1/2 (14.5 ounce) can lentils, drained with liquid reserved
- 1 teaspoon dried oregano
- 2 tablespoons chopped fresh parsley
- salt and ground black pepper to taste
- 1 cup crumbled feta cheese
- 1 1/2 tablespoons butter
- 2 tablespoons all-purpose flour
- 1 1/4 cups milk
- ground black pepper to taste
- 1 pinch ground nutmeg
- 1 egg, beaten
- 1/4 cup grated Parmesan cheese
- Sprinkle eggplant slices with salt and set aside for 30 minutes. Rinse and pat dry.
- Preheat oven to 375 degrees F (190 degrees C).
- Heat oil in a large skillet over medium-high heat. Rinse and pat eggplant dry. Cook eggplant and zucchini in hot oil until lightly browned on both sides, about 3 minutes per side; remove with a slotted spoon to drain on a paper towel-lined plate, reserving as much oil as possible in the skillet
- Adding more oil to skillet as needed and let it get hot. Cook potato slices in hot oil until browned, 3 to 5 minutes per side; remove with slotted spoon and drain on a paper towel-lined plate, again reserving oil in the skillet.
- Saute onion and garlic in reserved oil until lightly browned, 5 to 7 minutes. Pour in vinegar, bring to a boil, and reduce heat to medium-low; cook until liquid is reduced in volume and thick. Stir in tomatoes, lentils, 1/2 the juice from lentils, oregano and parsley. Cover, reduce heat to medium-low, and simmer 15 minutes.
- Layer about 1/3 of the eggplant, 1/3 of the zucchini, 1/2 the potatoes, 1/2 the onions, and 1/2 the feta into a 13×9-inch baking dish. Pour tomato mixture over vegetables; repeat layering, finishing with a layer of eggplant and zucchini.
- Cover and bake in preheated oven for 25 minutes.
- Stir butter, flour, and milk together in a small saucepan; bring to a slow boil, whisking constantly until thick and smooth. Season with pepper and nutmeg; stir. Remove from heat, cool for 5 minutes, and stir in beaten egg.
- Pour sauce over vegetables and sprinkle with Parmesan cheese. Bake, uncovered, for another 25 to 30 minutes.