Here is another recipe I adapted from the 1950's better Homes and Garden cookbook: the recipe was full of overly processed ingredients I just brought it back to basics.
6 slices sourdough bread
2 tablespoons softened unsalted butter
6 ounces Emmenthal, Gouda, or Monterey Jack cheese, sliced
6 slices prosciutto
10 slices of cooked ham
½ cup thick béchamel sauce - See Croque Monsieur for recipe.
Baby salad greens
1 tablespoon snipped chives, for garnish
Heat oven to 400. Lay bread slices on a work surface. Lightly butter 3 slices and place butter-side-down on a baking sheet. Now spread them lightly with mustard.
Place salad greens on the bread, followed by ham, cheese, a slice of bread, and press down.
Spread each top slice with about 3 tablespoons béchamel. Place Prosciutto on top and more cheese if desired.
Bake until browned and bubbling on top, about 10 minutes. To serve, cut each sandwich in half diagonally or vertically to make 6 small sandwiches. Sprinkle with more baby salad greens and chives. Cut off crusts if desired. May also be cut into bite-size pieces.