Mashed potatoes replace cream sauce and ground lentils replace lamb in a casserole that serves a crowd. If you don't have a deep (3 inches) baking dish, make this in two separate dishes.
1. Cook potatoes and garlic in boiling salted water 10 minutes, or until soft. Drain, and reserve liquid. Mash with 1/4 cup olive oil and 2 cups cooking liquid. Season with salt and pepper.
2. Heat 2 Tbs. olive oil in saucepan over medium heat. Add onion and oregano, and sauté 5 minutes. Add tomatoes, lentils, bay leaf, cinnamon stick, and 3 cups potato cooking liquid. Cover, reduce heat to medium-low, and simmer 45 minutes, or until lentils are tender. Remove bay leaf and cinnamon, and purée lentils in food processor until chunky. Season with salt and pepper.
3. Place eggplant slices on paper-towel-lined baking sheet, and sprinkle with salt. Let stand 30 minutes. Rinse, and pat dry.
4. Preheat oven to 350˚F. Coat deep 13- x 9-inch baking dish with cooking spray. Spoon 1 1/2 cups lentil mixture into bottom. Top with eggplant, followed by zucchini and tomatoes. Spoon 2 cups lentil mixture over top. Spread half of potatoes over lentil mixture. Top with remaining eggplant, and lentil mixture. Spread remaining potatoes over top, making sure to cover completely. Bake 1 1/2 hours, or until top is browned.