Prepare your pellet grill for 225 degrees F.
Form ground beef into 6 equal-sized patties, about 1 to 1 ½ inches thick. Make a small indentation in the center of each parry. Season with salt, pepper, or BBQ rub.
Place burgers into the pre-heated pellet grill. Close lid and cook patties for 30 minutes, flip the burgers, and cook for 30 minutes more.
Optional step: Smoking the onions. Slice them thin and toss them with seasonings and oil. Place them into a disposable aluminum pan and cook for 45 minutes to an hour or until they are tender and caramelized.
Once the hamburger patties are near done (internal temperature of 155 degrees F), top each with a slice of cheese. I recommend sliced blue cheese, pepper jack, American, or cheddar for these smoked burgers. Cook for an 3-4 minutes until cheese has melted.Burgers are done once they reach between 160-165 degrees F.
Remove from grill and assemble your burgers wit sliced tomatoes, lettuce, raw or smoked onions, burger sauce (see below), and bacon.
Note: You can use barbecue sauce as a topping. Or mix 1 cup barbecue sauce with 1/3 of cup of mayonnaise for a creamy burger sauce.
Store leftover smoked burger patties in an airtight container in your refrigerator for up to 3 days. Reheat in a 325 degree oven, microwave, or in a skillet on your stovetop.