onion — sliced

The onion (Allium cepa) is a bulbous plant in the amaryllis family, cultivated worldwide for its pungent, layered bulb. Native to Central Asia, onions have been domesticated for over 5,000 years and are now grown on every continent. The bulb consists of concentric layers of fleshy leaves surrounding a central shoot, with papery outer skins ranging from golden to red to white depending on variety. When cut, onions release volatile sulfur compounds that produce their characteristic sharp, acrid aroma and peppery flavor. Common varieties include yellow onions (sweet and mild when cooked), red onions (milder and sweeter), and white onions (crisp and best used raw). Sliced onions are cross-sectional cuts of the bulb, exposing the concentric rings and maximizing surface area for cooking.

Sliced onions serve as a foundational aromatic in countless cuisines, used as a base for soups, stews, and braises where they caramelize and provide deep sweetness and umami. They are essential in French mirepoix, Latin sofrito, and Italian soffritto. Sliced onions are grilled or sautéed as a side dish, feature in stir-fries and fajitas, and appear raw in salads, sandwiches, and relishes for their crisp texture and sharp bite. Thin slicing increases surface area for even cooking and caramelization, while thicker slices maintain structural integrity in high-heat applications. The choice of onion variety affects the final dish—yellow onions are preferred for cooking, while red and white onions excel raw or for quick-pickled preparations.