I understand people eat differently and like different things but to all the above I'll just say Ugh! It looks and sounds like people have run out of good ideas. Of course you could use butter. You could use butter and mustard or catsup. Throw a slice of bacon or two and use bacon grease. That may be a good idea after all. Maybe the nature of it all is exploration.
Olive oil has a higher smoker point than butter, and these are baked at 400°. If it were me and I really wanted to use butter, I would clarify it first. That will raised its smoke point, and it will taste better.
Butter is about 25% water. Clarifying butter merely means to separate out the water and solids. So you: 1-Melt the butter in a saucepan over a low heat 2-Let it separate into 3 layers --foam on top --middle layer is the butterfat --bottom layer is the water and most of the solids 3-Skim off the foam 4-Ladel out the butterfat (or pour off the butterfat while getting NONE of the water with it) This gives you a high smoke point and will not sputter when you heat it, because all the water is out of it. Think of the way bacon fat just melts when it hits a hot pan, versus the way regular butter sizzles and sputters (because of the water in it), and you get the idea of what clarifying does. This is like the drawn butter that you get as a side at a lobster restaurant...it's a clear golden liquid that almost looks like translucent colored water (because the impurities have been removed.)
@Bill Boggs I don't eat all that much butter on my foods, but I do sauté with is every once in a while. And I use olive oil. And bacon fat. And duck fat. And lard. And shortening. And peanut, canola and vegetable oils. All in moderation.
These are called Cheese and Herb Potato Fans. Lots of butter. I bet they're good, but they remind me of grub worms.
I believe that's referred to as Hasselback style. And lots of folks eat grub worms. I imagine that the hunt's not much of a challenge, but they're easy to prep.