Make honey mustard sauce by combining all ingredients in a bowl and stirring until smooth. Cover and refrigerate until ready to use (can be made in advance).

Optional: Spread a thin layer of honey mustard sauce on the insides of the bread slices.

Layer sandwiches with 3 slices of cheese (or more!) and a slice of ham. Heat a skillet over medium-low heat. Butter the outsides of the sandwich bread.

Cook: Add the sandwich to the hot skillet and cook for 2-3 minutes, until golden. Flip to the other side and cook for a few more minutes until cheese is melted and bread is golden brown. Serve warm, with honey mustard sauce for dipping.