How to Make It
Fill a pellet container to an electric pellet grill with hardwood pellets according to manufacturer’s instructions. Set temperature to 415°F, close lid, and preheat pellet grill 10 to 15 minutes.
Combine beef, mustard, paprika, onion powder, garlic powder, salt, and pepper in a large bowl. Shape into 6 (4-inch-wide) patties.
Place bacon in a large cast-iron or other heatproof skillet, and place on grill grate. Close lid, and grill until bacon is mostly crisp and most of fat is rendered, 25 to 30 minutes. Remove bacon from skillet, and drain on paper towels. Drain drippings from skillet; do not wipe skillet clean.
Melt butter in skillet on grill. Add soy sauce and Worcestershire sauce to skillet, and swirl to combine. Add onions to skillet, and place on 1 side of grill. Place patties on opposite side, and close lid. Grill until a meat thermometer inserted in patty registers 130°F to 135°F, 7 1/2 to 10 minutes per side. Top patties with cheese slices, cover, and grill until cheese is melted, 1 to 2 minutes. Place buns on grill, cut side down, and grill until toasted, about 1 minute.
Spread mayonnaise and ketchup evenly on cut sides of buns. Place patties, bacon, and onions on bun bottoms; cover with tops, and serve immediately.