Preheat oven to 375°F. Arrange bacon on a slotted broiler pan and bake to crisp 15-18 minutes.
If the bread you are using has a crispy crust, cut 12 slices and trim crust of 3. If using pre-packaged rather than freshly baked bread, this is unnecessary.
Slice and clean leeks, drain well. Heat 2 tablespoons butter in medium skillet. Add leeks and sauté to tender, 3-4 minutes. Season with salt and pepper.
Build sandwiches: a slice of bread, Swiss slice, leeks, tomato slice, bacon, Swiss slice, trimmed (if using) crust slice of bread, cranberry sauce or chutney, cheddar, turkey, ham, cheddar, bread.
Heat griddle pan over medium heat. Rub griddle with butter.