half of an onion

ProduceYear-round; onions store exceptionally well and are available in most markets throughout the year. Peak harvest occurs late summer through fall, with storage onions providing supply during winter and spring months.

Low in calories but rich in vitamin C, dietary fiber, and antioxidants including quercetin; contains prebiotic inulin that supports digestive health.

About

The onion (Allium cepa) is a bulbous vegetable belonging to the allium family, native to Central Asia and now cultivated worldwide. It consists of concentric layers of fleshy scales surrounding a central shoot, with a dry, papery outer skin that ranges in color from golden, white, to deep purple depending on variety. The flavor profile evolves significantly with preparation: raw onions possess sharp, pungent sulfurous compounds that provoke tears when cut; cooking transforms these volatile compounds into sweet, caramelized sugars. Major cultivars include yellow/Spanish onions (mild when cooked), white onions (sharper, used in fresh applications), red/purple onions (sweet and visually striking), and sweet varieties like Vidalia and Walla Walla.

Culinary Uses

Onions serve as a foundational aromatic in nearly all world cuisines, functioning as the flavor base for stocks, soups, sauces, and sautés. They are used raw in salads, salsas, and pickles for their crisp texture and sharp bite; caramelized as a sweet condiment or base for French onion soup; grilled or roasted as a side dish; and minced into ground meat preparations. Beyond savory applications, onions appear in Asian cuisines (stir-fries, curries), Mediterranean cooking (soffritto base), and Latin American dishes (sofrito). The degree of heat applied fundamentally alters their contribution: gentle heat over extended time yields sweetness, while high-heat searing develops deep caramelization and umami complexity.

Forms & Preparations

  • Diced — Cut into small cubes, standard preparation for sautéing as an aromatic base or for raw applications like salsas and relishes.
  • Sliced — Cut into thin rings or half-moons, used for caramelizing, grilling, roasting, or layering in raw salads and sandwiches.
  • Minced — Finely chopped to near paste-like consistency, used for deeply integrated flavor in ground meat mixtures, marinades, and condiments.
  • Caramelized — Slowly cooked over low heat for 30-45 minutes until golden brown and deeply sweet, used as a condiment, soup base, or topping.
  • Roasted or grilled — Halved or quartered and cooked with dry heat until charred and tender, served as a side dish or incorporated into composed plates.
  • Pickled — Raw or cooked onions preserved in vinegar-based brine, used as a condiment, garnish, or component of ceviche and other acidic dishes.

Substitutes

  • Unknown — Use equal weight; shallots are milder and sweeter, suitable for applications emphasizing delicate flavor; work well raw or cooked but require slightly less cooking time.
  • Unknown — Substitute at 1:1 by weight; milder and less pungent, best in cooked applications like soups and braises; white and light-green parts are most tender.
  • Unknown — Use 1/4 to 1/3 the weight of onion called for; much more pungent and concentrated, best in applications where strong allium flavor is desired rather than sweetness.
  • Unknown — Use 1.5-2x the weight; milder and fresher-tasting, best in raw applications or as garnish; lack the cooking-sweetness of mature onions.
  • Unknown — Use as garnish or finishing element only; delicate onion flavor without the substance or cooking properties of whole onions.