How to Make It
Preheat oven to 450°F. Toss eggplant with salt and wrap tightly in aluminum foil. Place on a baking sheet and roast until very soft, about 20 minutes. Unwrap; let stand for 10 minutes.
Transfer eggplant to a food processor. Add tahini, lemon juice, garlic, and pepper; process until smooth. With processor running, stream in oil until smooth and incorporated, scraping down sides of bowl as needed.
Transfer eggplant dip to a bowl; drizzle with oil and sprinkle with sumac, if using. Serve alongside pitas, cheese, and crudités.