Pan-Thai — red shallots are the universal base allium; onion is the Muslim-influenced exception
Thai cooking uses red shallots (hom daeng, Allium cepa var. aggregatum) as the default allium — not white or brown onions. Shallots are smaller, more pungent when raw, sweeter when cooked, and have a more delicate texture that breaks down fully in curry pastes and caramelises beautifully when fried. They appear in curry pastes (pounded raw), as crispy shallots (hom jiaw — fried until golden-brown), in yam salad dressings, and as whole roasted shallots in certain Northern pastes. Yellow or white onions (hom hua yai, 'big onion') are used in massaman curry and dishes with Muslim-Malay influence, and increasingly in stir-fries, but are considered a foreign ingredient in classical Thai cooking.
Crispy shallots (hom jiaw) are the textural and flavour exclamation point of Thai noodle soups and rice dishes — their sweet-savoury crunch and caramelised onion aroma is one of the defining top notes of the cuisine as experienced at street level.
{"For curry pastes: red shallots pounded raw — they provide body, sweetness, and pungency","For crispy shallots (hom jiaw): slice evenly thin (2mm), toss in a small amount of flour, fry in cool oil slowly","Roasted shallots for Northern pastes: char whole, unpeeled shallots directly over a gas flame or dry pan","Shallots in yam dressings: slice paper-thin and marinate 5 minutes in lime juice to temper sharpness","1 large European shallot ≈ 3–4 Thai shallots in volume but is less pungent and less sweet when cooked"}
The best hom jiaw is cooked in a generous depth of oil (deep-fry rather than shallow-fry) starting at room temperature, slowly heated to 160°C, then the shallots are added and the oil brought to 180°C. This slow-heat method produces deeply golden, sweet, crispy results. Drain on paper and do not salt until serving — salt causes them to lose crunch within minutes.
{"Substituting yellow onion in curry pastes — it is too watery, too mild, and will not break down the same way","Cutting hom jiaw too thick — 3mm+ slices won't crisp before the outside burns","Adding shallots to screaming-hot oil for hom jiaw — they burn on the outside before drying out","Using Western banana shallots in Thai preparations — they are milder and lack the necessary pungency"}