1 1/2 pounds ground bison

5 tablespoons mayonnaise, divided

2 teaspoons salt

1/4 cup instant coffee crystals

3 tablespoons brown mustard

5 - 7 slices Gruyere cheese

5 - 7 pretzel rolls

Form 5 - 7 small bison patties (a little smaller than a regular hamburger).  Brush each side with mayonnaise (about 2 tablespoons in total).  Place patties on grill.  Season with half the salt and coffee.  Allow to cook a couple of minutes until they firm up.  Flip and season second side.  Cook a few minutes and flip again to sear second side.  Cook just until done (don't undercook bison).  Mix remaining mayonnaise with mustard.  Place about a tablespoons worth on top of each burger.  Put cheese on top and close lid of grill.  When cheese melts, they're ready!  Makes 5  - 7 sliders.