Flavour Bases
Both Asian spice bases for curries, soups and sambals or European Sofrito (onion, garlic, and tomatoes), and Mirepoix (onion, carrot, celery, garlic) for European type stews and so many of the world's greatest dishes—from paella to chicken fricassee and jambalaya are built on a basic recipe foundation that requires onions and garlic gently sautéd in oil. Almost every cuisine in the world starts with the humble beginnings of this simple, vegetable base.
Origins of Flavour
How this originated requires a look at the native geography of those two base ingredients that belong to the Allium family. The exact origin of the onion is debated, but it's widely believed to have originated in Central Asia, including regions like Iran, western Pakistan. While many archaeologists, botanists and food historians believe onions originated in Central Asia, other research suggests that onions were first grown in Iran and West Pakistan. Garlic (Allium sativum) is native to Central Asia, specifically regions including Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan. It also has a historical presence in South Asia and northeastern Iran.
It cannot be determined if onions and garlic used this way as a base originated from either the East or the West, but originated independently in each, then specific ingredients found in those local regions would determine how those recipes evolved. Carrots native to Central Asia, Afghanistan, Iran, and parts of Uzbekistan, Celery native to the Mediterranean region and parts of the Middle East, Chillies from South America brought to Asia by the Portuguese, Black pepper and Mustard seeds from India and Lemongrass, Galangal and Candlenut native to South East Asia would further develop that onion garlic savoury base into their many culinary variations.
Saute Onions
saute(n.) "a dish cooked by being fried in a pan over high heat," 1813, from French sauté, literally "jumped, bounced" (in reference to tossing continually while cooking), past participle of sauter "to jump," from Latin saltare "to hop, dance," frequentative of salire "to leap" (see salient (adj.)). As an adjective, "fried quickly," from 1869. As a verb from 1859. Related: Sauteed. French saut also was borrowed 19c. as a ballet term.
Sautéing onions enhances their flavour, softens them faster, and allows for the creation of new flavor compounds through the Maillard reaction. The original French word "sauté" has a very specific meaning. It requires very high heat, so high that the vegetable pieces would scorch if left for more than a few seconds on the pan - so they are continuously moved around in a "jumping" motion. This is the meaning which is used in cooking textbooks and what cooking professionals are taught. Sauteing for a sofrito or tumis for a sambal however now follows another meaning: "shallow frying" "sweating" or "caramelizing". The word has shifted somewhat in its application
Fried Onions & Garlic
Fried onions and garlic are also used as a garnish for centuries across different cuisines- sprinkled on green bean casseroles in the US, Briyani in India and over fried rice and Laksa in South East Asia. In the United States, deep-fried onions and onion rings gained popularity in the 1920s and 30s, as a vegetable side. In Indian cuisine, they are sometimes used as a base for curries and gravies. In South East Asia they add more savoury notes when used as a base for Sup Kambing and Soto.
Raw Onions
Raw onions offer a pungent, crunchy flavour in Western salads and sandwiches, stretching into Middle eastern and South European cuisine. In South American cuisine hey are a key ingredient in many salsas and relishes that are used as dips or toppings on tacos. In Asia they are used similarly in Indian Raitas and Malay uncooked sambals made of fermented shrimp fry and vinegar. Other members in the onion family add more nuance to this culinary picture, chopped leafy chives, garlic chives and green scallions
Pickled Onions
Pickled onions appear as condiments in Europe and US as a side or in sandwiches. In South and SE Asia they can be found in Achars and in Chinese and East Asian cuisine they are similarly used as condiments to complement a meal of rice accompanied with other dishes.