where is this sort of cooking originated from?
Frying food in olive oil is attested in Classical Greece from about the 5th century BCE.
Deep frying
Frying food in olive oil is attested in Classical Greece from about the 5th century BCE. 
where does the oil for frying potato chips come from Europe what does deep frying mean? It  is a cooking method in which food is submerged in hot fat, most commonly oil
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Deep frying [SEP] History
The English expression "deep-fried" is attested from the early 20th century. Frying food in olive oil is attested in Classical Greece from about the 5th century BCE. The practice of deep frying spread to other parts of Europe and Arabia in the following centuries. Deep-fried foods such as funnel cakes arrived in northern Europe by the 13th century, and deep-fried fish recipes have been found in cookbooks in Spain and Portugal at around the same time. Falafel arrived in the Middle East from population migrations from Egypt as soon as the 14th century. Evidence of potato frying can be found as early as the late 17th century in Europe.