1 large eggplant (about 1 1/2 pounds)
2 1/2 tablespoons extra-virgin olive oil
1 tablespoon unsalted butter
1/4 cup finely chopped onion
2 tablespoons minced shallot
1 tablespoon minced garlic
1 1/2 cups arborio rice (10 ounces)
1/4 cup dry white wine
3 cups hot vegetable stock or broth
1/4 cup heavy cream
Salt and freshly ground pepper
2 tablespoons minced flat-leaf parsley
2 scallions, thinly sliced
Ground sumac (see Note)
Light a grill. Rub the eggplant with 1/2 tablespoon of the oil and grill over moderate heat, turning occasionally, until charred and soft, 20 minutes; let cool slightly. Halve the eggplant lengthwise and scoop the pulp into a blender. Puree until creamy.
In a large saucepan, melt the butter in the remaining 2 tablespoons of oil. Add the onion, shallot, garlic and rice and cook over moderate heat, stirring, until fragrant, 5 minutes. Add the wine and cook until it is absorbed. Add the vegetable stock, 1/2 cup at a time; stir constantly until it is absorbed before adding more. Cook until the rice is al dente, 20 minutes total.
Stir in the eggplant puree and the cream and season with salt and pepper. Stir in the parsley and scallions. Spoon the risotto into bowls, sprinkle with sumac and serve.