3 pounds ground chuck
1 to 2 large red onions, diced
Large handful of fresh flat leaf parsley, chopped
2 tablespoons oyster sauce
2 tablespoons ketchup
1 egg yolk
Mix the beef, onions and parsley together. Add the remaining ingredients and mix well.
Divide into six equal portions and roll each one into a large ball. Refrigerate for at least one hour.
Preheat the barbecue for 10 minutes. Place burgers on grill and cook a few minutes on each side over high heat, just until starting to brown. Then move the burgers to the side, where it is slightly cooler, to finish cooking.