01 -
Stir together the mayonnaise, Worcestershire sauce, lemon juice, garlic powder, smoked paprika, and Cajun seasoning in a small bowl. Cover and refrigerate while you prepare the rest.
02 -
Melt the butter in a skillet over medium-low heat. Add the sliced onions and cook slowly for 20 to 25 minutes, stirring occasionally, until soft and golden brown.
03 -
Combine the garlic powder, onion powder, smoked paprika, and Cajun seasoning in a small bowl.
04 -
Divide the ground chuck into 6 portions. Shape each into a patty about 3/4 inch thick. Press 3 to 4 cubes of pepper jack into the center of each and pinch the meat closed to seal. Flatten gently.
05 -
Pat the patties dry and season both sides with the rub. Arrange on the smoker grate at 250°F with hickory or pecan wood. Smoke for 30 to 40 minutes until the internal temperature reaches about 150°F.
06 -
Lay a slice of Colby jack 3 pepper cheese on each burger. Close the lid and cook 2 to 3 minutes more, until the cheese is melted and the internal temperature reaches 160°F.
07 -
Butter and toast the buns on the smoker or a grill pan for about 1 minute. Spread Cajun sauce on both halves, add the patty, pile on caramelized onions, and cap with the top bun.