Pennsylvania Dutch potato filling…
Three sticks of butter and a death wish.
Edited with the recipe with the following changes.
Use all of the butter for the frying of the bread and vegetables. Do not put any on top. Not necessary. You may even need extra butter, hence this time I needed three sticks. I used salted.
In the UK, use size medium eggs. In the US, size large.
You can season it however you would like.