1. preheat the oven to 400F.
2. build the sandwich. each sandwich should be made like this:
- spread 1 teaspoon of mayonnaise on one slice of bread
- spread 1 teaspoon of mustard on the other slice of bread
- stack up: 1 slice of swiss cheese, 2 slices of prosciutto, and 1 slice of turkey
3. heat up some butter on a frying pan. (medium to low heat is good enough, otherwise the butter will burn and your smoke alarm will go off.) grill the sandwich for 2 mins on each side (total 4 mins).
4. put all the sandwich in the oven for 4 mins (i.e. until the cheese is thoroughly melted).
5. ready to serve!
Tip: Best prosciutto in Boston: Salumeria Italiana, North End