The Wikipedia article says there’s probably little if any actual Amish heritage to this recipe, although sharing a sourdough starter IS part of Amish culture. As evidenced in the recipe variations at the website linked above, there are versions without the pudding mix, but it does make a moister loaf.
Since I last posted, I’ve done a loaf with Solo almond filling, sliced almonds, and rhubarb, and a coconut version using coconut milk, virgin coconut oil, shredded coconut, and almonds. Both are delicious. A friend likes the coconut best, but I still give top marks to the creamsicle variation, second best to the original cinnamon/walnut/sultana loaf. They keep very well in the fridge. I had the last piece of my first loaf 4 weeks to the day since it was baked, and it was still great, though the crunch of the sugary crust had softened away, as is to be expected.