12 green onions, rinsed, ends trimmed
2 cloves garlic, minced
2 tablespoons butter, cut into small pieces
salt and ground black pepper to taste
Preheat a grill for medium-low heat.
Cut a sheet of aluminum foil to about 12×15 inches. Arrange the green onions side by side in the center of the foil sheet. Sprinkle the onions evenly with the garlic, salt, and pepper. Arrange butter over the onions. Keeping the green onions flat, fold the foil to make a sealed cooking pouch.
Place the foil packet on the preheated grill away from the main heat source. Allow the green onions to steam 5 to 7 minutes.