- ¼ cup balsamic vinegar
- 2 garlic cloves, finely minced
- 3 tablespoons chopped fresh lemon thyme
- 2 pounds medium to large red onions
- About ½ cup extra virgin olive oil
- Kosher salt and freshly ground black pepper
- Preheat a gas grill or prepare a fire in a charcoal grill.
- Combine the vinegar, garlic, and thyme in a small saucepan and heat until fragrant and just beginning to steam (the mixture will register about 150°F on an instant-read thermometer); don’t let it boil. Remove from the heat and let stand for 20 minutes.
- Meanwhile, cut the onions into ½-inch-thick slices and layout on a baking sheet. (To make it easier to turn the onions on the grill, and to avoid losing any onion rings in the fire, insert a toothpick into the side of each slice, pushing it halfway through; or put a wire cooling rack on the grill so the onions won’t slip through.) Brush on both sides with 3 to 4 tablespoons of the olive oil and season with salt and pepper.
- Place the onions on the hottest part of the grill and cook, unmoved, for 4 to 5 minutes, until just charred on the first side. Turn and cook for 3 to 4 minutes more, or until softened and lightly charred on the second side. Transfer to a baking sheet or platter and remove the toothpicks if you used them, then carefully stack the onion slices–like pancakes–on a serving platter.
- Whisk the remaining ¼ cup olive oil into the vinegar mixture and drizzle it over the onions. Serve warm or at room temperature.