Heat olive oil in a medium-sized saucepan.
Add garlic and onion and cook until onion turned soft.
Add za'atar, salt, and ground pepper.
Mix, then add the scooped roasted eggplants and stock.
Cover the pan with a lid, bring to a boil, then simmer for about 10 minutes.
Add yogurt and mix to combine.
Use an immersion blender to puree the roasted eggplants.
Add lemon juice, taste, and adjust seasoning.
Bring to a slow boil, then take the pan off the heat.
Transfer eggplant soup into bowls and serve with a drizzle of olive oil and za'atar.