Put the tomatoes over 2 gas burners on high and cook, turning occasionally, until charred and peeling. Alternatively, broil the tomatoes until charred. Put the tomatoes in a bowl and cover tightly with plastic wrap. Set aside to steam for 5 minutes. Peel and seed the tomatoes.
Transfer the tomatoes to a blender with the vinegar and garlic and puree until smooth. While the motor is running, drizzle in the oil until incorporated. Season with pepper, to taste.
Yield: about 2 cups