Mix the sauce ingredients in a medium bowl until blended. Set aside.
In a separate bowl mix the ground beef, accent seasoning, Lawry's seasoned salt and pepper with your hands until all is combined.
Divide the mixture into four patties.
Place the patties onto the fry pan or grill. Cook for 7 minutes per side until done.
Once the patties are done, add 1/4 of the cheese to each patty. Cover and let it melt for a few minutes.
Meanwhile, heat butter in a separate pan on medium heat. Add buns and toast until golden brown.
To assemble the burgers, put a patty on each buns. Add 1 tablespoon of the hardees mushroom swiss burger sauce. Add extra cheese and top with another bun.