The Best Ever Grilled Onions

1. Hold an onion on a cutting board with the root end facing sideways. About 3/4 inch in from the root, drive a wooden skewer through the center of the onion, pushing it all the way through so the flat end sits next to the onion and the pointy end is as far away as possible.
2. On one side of the skewer, slice the root end off the onion. On the other side, leaving about 3/4 inch of onion, slice through so the skewer runs through the center of each slice. Use a knife to cut off the part of the skewer sticking out. Repeat until both onions are sliced into even slices about 3/4 inch thick, trimming excess skewer.
3. Brush the slices on both sides with olive oil and season with salt and pepper.
4. Charcoal grill: Build a two-zone fire, coals on one side and none on the other. Place the onions on the cool side and flip and rotate every 10 to 15 minutes until golden brown, usually 25-40 minutes. They are done when golden and tender.
5. Gas grill: Heat the grill 5-10 minutes, then lower the burners to low and cook the onions on the low burner, flipping every 10 minutes until golden brown, about 25-40 minutes.

Tips: use sweet onions so the sugars caramelize; cook low and slow so the outside doesn't burn before the inside is done; slice evenly for even cooking.