Grilled Sweet Onions Recipe

Prepare onions

Trim the onions by cutting off the root end just enough to remove loose root fibers but keep the root base intact so the layers stay together while grilling. Trim the top (stem) end to remove about 1/4 inch. Peel off the outer papery skin, leaving the first thin translucent layer if intact. Pat dry.

Slice and assemble (two methods)

Method A - Thick slices: Place each onion on its side and slice into 3/4- to 1-inch thick rounds. Keep rounds intact; smaller outer rings can be tucked together. Method B - Halves for wedges: Cut each onion through the root into two even halves. Both methods work; thick rounds yield nice rings, halves give larger grilled segments.

Make oil-butter mixture

In a small bowl, whisk together the extra-virgin olive oil, melted butter, minced garlic, thyme, apple cider vinegar, honey (if using), kosher salt, and black pepper until combined.

Preheat grill or pan

Preheat an outdoor gas grill to medium-high (approx. 375–425°F / 190–220°C) or heat a cast-iron skillet or grill pan over medium-high heat on the stovetop. If using a charcoal grill, set coals for even direct heat. Oil the grill grates or brush the skillet with a thin film of oil to prevent sticking.

Brush and season onions

Brush both sides of the onion slices or halves generously with the oil-butter mixture, making sure some of the minced garlic and thyme adhere to the cut surfaces.

Grill onions

Place onions on the preheated grill or skillet cut side down (for slices/halves). Grill for 4–6 minutes without moving until well-marked and caramelized on the first side. Flip gently with a spatula or tongs and grill the other side 4–6 minutes more, basting once with remaining mixture, until onions are tender and a bit translucent through the center. Total cook time per piece will be 8–12 minutes depending on thickness and heat.

Finish and rest

Move onions to a cooler part of the grill or a plate and let rest 2 minutes. Taste and adjust seasoning with a pinch more salt, a grind of pepper, or an extra splash (1/4 tsp) of vinegar if desired.

Transfer grilled onions to a serving platter. Sprinkle with chopped fresh parsley and crumbled feta or goat cheese if using. Serve warm with lemon wedges on the side for squeezing over the onions.