Prepare a grill for cooking over medium-high heat. In a large bowl, combine the bison with the red onion, breadcrumbs, ketchup, parsley, Worcestershire, chili powder, garlic powder, egg and some salt and pepper. Form 4 patties, and stuff each with a cube of Cheddar, enclosing completely within the meat.
Lightly oil the grill grates. Cook the patties, turning once, until cooked through, 12 to 15 minutes total. Remove from the grill and place on pretzel buns. Top with the Shaved Brussels Slaw and spread the Rosemary Ketchup on the bun tops. Serve.
Shaved Brussels Slaw:
Shave the Brussels sprouts using the small holes on a box grater. Combine with the granulated sugar, vinegar, red pepper flakes and some salt and pepper in a large bowl and stir to combine.
Stir together the ketchup, brown sugar, rosemary and some salt and pepper in a small bowl using a whisk.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.