If you have ever lived far from home, you know that food can be a surprisingly powerful form of homesickness therapy. One bite of boerewors, a spoonful of chakalaka and suddenly you are back at a South African braai. Mark Henegan took that idea considerably further. The Benoni-born chef carried the flavours of South Africa across the Atlantic and into New York, where his restaurant became a meeting place for South Africans, celebrities and curio…