Spread mayonnaise on one side of one slice of bread. Spread mustard on one side of the other slice of bread. Lay down, spread sides up.
Top each slice of bread with spread with a slice of Swiss cheese.
Top one slice of bread with the Swiss cheese with the ham. Assemble the sandwich.
In a small bowl, beat the egg and the half and half until well combined.
Heat a small skillet over med heat. Add the butter and swirl it around. Once it’s all melted and starting to bubble, dip the sandwich quickly in the egg, making sure to coat the entire thing. Add sandwich to skillet and cook until golden brown on one side, Flip and cook the other side. Serve warm with powdered sugar and strawberry preserves, if desired.