It used to be that the way for an amateur cook to get a cookbook deal was to reach out to publishers and pitch their idea, then wait for the reply – usually, a rejection. Now, thanks to social media, publishers are contacting popular Instagramers who are creating original content, and asking them if they are interested in writing cookbooks instead. A physical cookbook is a longer-lasting legacy than a social media account – it’s something that can be given to friends or loved ones, or handed down to younger family members. Michael Zee, 35, knows something about legacies –…