To prepare sauce, heat 1 teaspoon oil in a large nonstick skillet over medium-high heat. Add onion; sauté 5 minutes. Add tomato, ginger, and minced garlic; sauté 5 minutes or until tender. Add spinach, and sauté 3 minutes. Add 1 cup water; cook 5 minutes or until liquid evaporates. Remove from heat; cool. Spoon spinach mixture into a food processor; process until smooth. Lightly spoon flour into a measuring cup; level with a knife. Place flour into a small bowl; whisk in 1/4 cup water, 1/4 cup yogurt, and salt. Place spinach mixture in a medium saucepan; stir in flour mixture and remaining yogurt. Cook over medium heat 15 minutes or until the mixture begins to thicken, stirring frequently. Cover and remove from heat.
To prepare eggplant, place eggplant slices in a single layer on a baking sheet. Combine 1 teaspoon of oil, coriander, turmeric, and 1/4 teaspoon pepper. Using the back of a spoon, spread a small amount of mixture over 1 side of each eggplant slice. Broil 10 minutes or until lightly browned.
Heat 2 teaspoons oil in a small skillet over medium heat. Add 1/4 teaspoon pepper and sliced garlic; sauté 1 minute or just until garlic is lightly browned. Remove from heat. Pour warm spinach sauce in a shallow serving dish; top with eggplant. Drizzle with garlic mixture. Serve with rice.