The simple act of charring and puréeing eggplant flesh results in a deeply flavored, smoky base that’s incredibly silky. Add a finishing dollop of tzatziki for a cold, crisp contrast.
Make the soup: Heat oven broiler. Place eggplant cut side down on a baking sheet and prick all over with a knife. Broil, flipping once, until skin is charred and eggplant is tender, 15 minutes. Let eggplant cool, then peel and transfer to a blender along with the garlic. Add tahini, Aleppo pepper, lemon zest and juice, 2 cups stock, the yogurt, salt, and pepper; purée un