Stir brown sugar, sage, salt, basil, black pepper, onion powder, marjoram, and red pepper flakes together in a small bowl. Sprinkle over beef and use your hands to mix until evenly distributed. Cover and refrigerate until flavors have blended, about 24 hours.
Divide beef mixture into 8 patties.
Heat a large nonstick skillet over medium heat. Working in batches, cook patties in the hot skillet until firm and no longer pink in the center, 5 to 7 minutes per side. An instant-read thermometer inserted into the center should read at least 160 degrees F (70 degrees C).