In a small bowl, combine ½ cup of mayonnaise and ¼ cup of sweet barbecue sauce, whisk until smooth and set aside.

Heat vegetable oil in a Dutch oven to 375°F. In a bowl, mix ½ cup of milk with 1 tablespoon of vinegar and let sit for 5 minutes. Combine 1 cup of flour with seasonings, then dip onion rings into milk and coat with flour.

Carefully drop coated onion rings into hot oil, frying for about 3 minutes or until golden brown. Remove with a slotted spoon and drain on paper towels.

While the onion rings are frying, slice tomatoes and prepare lettuce, dill pickles, and cooked bacon. Arrange toppings on a serving plate.

Spread a thin layer of butter on cut sides of brioche buns, toast on medium heat for 2-3 minutes until golden brown.

Shape ground chuck beef into patties, season with salt and pepper. Grill for 3-5 minutes per side, adding cheddar cheese on the last minute to melt.

Spread smoky barbecue aioli on the bottom half of each bun, layer with lettuce, tomato, pickles, beef patty with cheese, bacon, and an onion ring, then top with the bun.

Serve immediately with extra crispy onion rings and your favorite side, like sweet potato fries.