x red onion

Red onion (Allium cepa var. purpureum) is a cultivar of the common onion distinguished by its deep crimson to burgundy exterior papery skin and layers, with red-tinged white flesh. Native to Central Asia and distributed globally, red onions belong to the Amaryllidaceae family. The color derives from anthocyanin pigments concentrated in the outer layers. Red onions typically measure 5–8 cm in diameter and possess a sweeter, milder flavor profile compared to yellow or white varieties, with less pungency when raw, though they develop sulfurous complexity when cooked.

Key cultivars include 'Red Burgundy', 'Red Baron', and 'Italian Red' (Tropea), each varying in size, sweetness, and storage capacity. The flavor is notably sweeter due to higher natural sugar content and lower levels of sulfur compounds relative to other onion types.

Red onions are versatile in both raw and cooked applications across numerous cuisines. Raw, they are preferred for fresh preparations such as salads, salsas, ceviche, and pickles, where their mild sweetness and visual appeal enhance the dish without dominating other flavors. They feature prominently in Mediterranean, Latin American, and South Asian cuisines. When caramelized or roasted, red onions develop concentrated sweetness and umami depth, making them suitable for tarts, gratin dishes, and composed salads. They are also used in braises, curries, and sautéed vegetable medleys. The color intensifies when cooked but may bleed slightly into adjacent ingredients, which is often desirable but worth considering in presentation.