Slice eggplant lengthwise into 1/2-inch-thick planks. Grill or broil them until moderately charred.
Meanwhile, place olive oil, onions, and garlic in large soup pot; cook on high heat, stirring frequently, until translucent.
Dice the charred eggplant, add it to the pot, reduce heat to medium, and cook 10 minutes, stirring frequently. Add tomatoes and cook 5 minutes. Add stock, lemon juice, and spices; simmer 30 minutes.
Let it cool a little, then puree in small batches. The color will be a rich brick hue. You may add salt and additional spices to taste.
Reheat the soup when you’re ready to serve it, garnishing each bowl with a lemon slice topped with a dollop of sour cream. The soup may also be served chilled in the summer.
Recipe Notes
This is a great soup to improvise with, adding other vegetables or fresh herbs if you have them.