Mix the ground beef, sazon, and a dash of Worcestershire sauce until combined. Slice the romaine lettuce and the tomatoes. Grate the cheese
On a medium temp flattop, place half pound balls of ground beef, flattening them to ½ inch thick patties. Brown and flip.
Add onions, toss with grease from the beef patties. Cook for 3-4 minutes or until softened.
Cover ground beef patties with the cooked onions then with cheese, cut it into the meat then cook until starting to melt. Flip the meat so cheese is down, letting it brown and crisp.
Optional - brown the rolls prior to loading them up. Add mayo to roll.
Load up the roll, add lettuce/tomatoes and wrap it in foil to serve. Add mustard/hot sauce/ketchup/mayo as desired.
