Use this on our Roasted-Garlic Turkey Burgers.
Preheat grill to high (if using a charcoal grill, coals are ready when you can hold your hand 5 inches above grill for just 1 to 2 seconds). Brush grill and the tomatoes with oil. Season tomatoes with salt and pepper.
Grill tomatoes until softened and slightly charred, 3 to 4 minutes per side. Let stand until cool enough to handle. Peel tomatoes; discard skins.
Put tomatoes, garlic, and oil in a bowl; mash with a fork. Season with salt and pepper. Sauce can be refrigerated in an airtight container, up to 3 days.