In a large pan, saute minced onion in olive oil until translucent.
Remove sautéed onions from the pan and set aside to cool.
In a large mixing bowl, combine ground beef, panko crumbs, egg, ketchup, salt and pepper.
Add sautéed onions to the beef mixture and combine.
Shape beef mixture into 4 oblong patties, about ¾ inch thick.
In the same large pan, on using a grill pan, on medium high-heat, sear the beef patties 3 minutes on each side. (See Gr8 Tip below if using a grill pan.)
Remove patties from the pan, cover and set aside.