I started doing it in 2007 (not doing a bit, I actually did - I had no money in uni and was getting so sweaty marching around in jeans that I made them into shorts, a practice that I still continue to this day). Love the jorts.
When I was a kid I came up with something I called a ‘cake pie’ for a food technology project, which was a pie base with a layer of jam in, and a sponge filling. Apparently, despite my love of bakewell tarts and frangipanes I believed this was a total innovation. I still call them cake pies in my head.