In a large bowl, gently knead the seasoning into the beef. Shape into patties and season with salt and pepper on both sides. Heat the grill to high heat and close the lid. Once the grill is heated turn it to medium high and add the meat. Cook for 3 minutes per side or until desired internal temperature. Meanwhile, mix the butter, seasoning and garlic powder and spread on each half of the bun. Grill them open side down until grill marks appear and set aside.