The pattern is titled Samira -- Apricot Baby Bonnet on the blog Crochetlatte. This is offered as a free pattern. I used a different yarn than that shown on this blog, so it has a different effect.
This bonnet does not have a brim, so if you really want a sun bonnet, this isn't for you. Adding a couple more rows is a good idea though if you want it to cover more of your baby's forehead. I think it looks really sweet on my darling baby, Juniper.