I just looked at the other thread & didn't read everything, but the recipes that I read were anything but healthy! Eg 1 cup flour, half a cup molasses & 1 cup sugar!!!
As I wrote there, occasional junk food treats in small quantities aren't likely to cause problems *unless* the horse is lami prone, overweight, IR or such(make sure you know). But why not stick to healthy treats, like some of what OP of that thread suggested; carrots, bits of apple, salad stuff, leaves, low-sugar fruit & veg, rosehips..... etc etc