This low effort/high payoff baked onion recipe yields the most meltingly tender, caramelized, savoury, and mellow onions you've ever eaten. Serve this unbelievably easy side dish with roasts, steaks, stews, and more.
Preheat oven to 425ºF with the rack positioned in the center.
Trim a thin disc from the root and blossom ends of the onion and cut in half across the equator of the onion. Remove the outer papery layer and place onion halves on a rimmed half sheet pan.
Drizzle the onions with the olive oil, then sprinkle on the salt and pepper. Gently rub the mixture over all surfaces of the onion halves. Arrange the onions cut side down on the pan, and roast for about 30 minutes, or until they are extremely tender and the cut undersides are deeply golden brown.
Let the onions stand for about 5 minutes before using a spatula to transfer them to a serving dish, cut side up. If desired, drizzle with balsamic vinegar and garnish with fresh herbs like thyme or parsley.
