Mix together the chuck, onion, pecans, bell pepper, Stubb’s Original Bar-B-Q Sauce, and Stubb’s Bar-B-Q Spice Rub. Shape into 3 large or 4 average-size patties. (The burgers may be mixed and shaped earlier in the day; refrigerate until ready to use.)
Prepare a grill for direct cooking. For a charcoal grill, when the coals are ashed over, rake or spread them out in the bottom of the grill so the food can cook directly over the coals. (For a gas grill, fire up the burners so the food can cook directly over the heat.)
Grill the burgers over direct medium heat, first on one side then on the other, 7 to 10 minutes, until they reach your desired degree of doneness. (Medium burgers register an internal temperature of 160°F.) Serve with lettuce, mayonnaise and toasted buns.