In celebration of the opening of Laurent Tourondel's newest NYC restaurant, L'Amico, we've asked him to share his secret to the sexiest onion ever.

By Justin Chapple
Updated June 28, 2017
Laurent Tourondel
Credit: © Justin Chapple

In celebration of the opening of Laurent Tourondel's newest NYC restaurant L'Amico—opening September 10th, adjacent to the Eventi Hotel—a group of Food & Wine editors were invited to a tasting of the new menu. Everything was incredible, from the sausage pie with shishito and fennel pollen to the spiced tuna with charred broccoli sprouts. But, without a doubt, one of our favorite dishes was a ginormous grilled rib-eye steak (it can seriously serve a whole table) that was accompanied by the most show-stopping onion we'd ever seen. It looked like a flower alongside the steak, and was perfectly tender and sweet. It was just tangy enough from a splash of balsamic vinegar and had a hint of smoke from the open fire in which it was cooked. Because we've been thinking of it ever since, we asked Laurent to share his secret. He happily obliged. Here's how they make this mad genius onion at L'Amico:

Ember-Roasted Red Onions with Balsamic and Rosemary
Makes 6

6 medium red onions
3/4 cup balsamic vinegar, plus more for drizzling
3/4 cup extra-virgin olive oil, plus more for drizzling
2 tablespoons finely chopped rosemary
Maldon sea salt and cracked black pepper

1. Using a sharp knife, trim 1/4 inch off the top and bottom of each onion, leaving the root intact. Cut each onion lengthwise to within a 1/2 inch from the bottom.

2. Lay a 12-by-12-inch sheet of heavy duty foil on a bowl. Put 1 onion root end down on top of the foil. Drizzle with 2 tablespoons each of the balsamic vinegar and olive oil, then season with Maldon sea salt, cracked black pepper and 1 teaspoon of the chopped rosemary. Fold up the foil and pinch the edges to seal the packet. Repeat with the remaining onions to make 6 packets. Let the onions marinate at room temperature for at least 1 hour and up to 2.

3. Light a hardwood or hardwood charcoal fire. When the coals are hot, create a bed of embers and set the onion packets directly on it. Cook until the onions are tender when pierced with a skewer, about 25 minutes. Transfer the onions to a baking sheet to cool, brushing off any embers. When the onions are cool enough to handle, unwrap and discard the foil. Carefully remove the burned outer layers of the onions and transfer the onions to plates or a platter, allowing the onions to open naturally. Drizzle with balsamic vinegar and olive oil. Season with Maldon sea salt and cracked black pepper before serving.