I learned something useful today when I put Kosciusko mustard on bread, added some thick slices of cheddar, and stuck the whole thing dry into the toaster oven for a double toasting. And that lesson is that such a sandwich comes out even crispier, and stays crunchy longer, than a sandwich grilled in butter. WIN!
also: Kosciusko mustard is very likely the most delicious mustard on earth. yum.