Slice bread length-wise and slather the inside generously with mustard on both the top and bottom pieces.
Layer on pork, ham, swiss cheese, and pickles. Place the top of the bread over top.
Spread softened butter over the outside of the bread (this really makes it). Place sandwich on a hot cast iron skillet and press a heavy pan or brick on top.
Cook until the sandwich is brown but not burned, and the cheese is melted. Cut the sandwich in half, if you haven’t already.
Notes
Depending on the size of your skillet/bread, you have have to cut the sandwich in half before pressing it.