I first tasted these a year ago on holiday in Vegas and there's nothing like them in Britain. Not even at American or Mexican themed restaurants. (Although admittedly these do not really resemble proper Mexican tamales, despite the name.)
These are light, creamy sweet little 'pudding' shaped corn cakes. I spent the last couple of years using different recipes and modifications trying to re-create them at home, and the recipe you see below is absolutely the closest you are going to get.
Recipe posted by Baking Phoenix