The umami factor starts with the beef itself, then is increased with Worcestershire sauce, mushrooms, and onions.
1 tablespoon Worcestershire sauce
1 teaspoon Vegemite or Marmite
1 1/2 pound ground beef (ideally 1/3 dry aged rib eye, 1/3 boneless short rib, 1/3 hanger steak, or your favourite blend)
2 tablespoons dried moral mushrooms or any other kind of dried mushrooms (use a mortar and pestle or a coffee grinder)
1 teaspoon dry mustard
2 teaspoons salt
1 teaspoon black pepper
4 airy burger buns (ideally brioche)
4 ounces blue cheese or Gruyere or your favourite burger cheese, crumbled or grated
2 tablespoons butter, at room temperature
6 tablespoons caramelized onions
4 tablespoons ketchup
In a small ramekin, mix Worchestshire and vegemite.
In a large bowl, add the ground beef. Add the Worcestershire and vegemite blend, mushroom powder, and mustard. Mix but do not overmix.
Form four beef patties. Season both sides with salt and black pepper.
Preheat the grill to direct medium-high heat.
Grill the burgers for about four minutes per side or until they are cooked to your desired degree of doneness.
Halfway through grilling the second side, top with the cheese and close the lid to help the cheese melt.
To Pan Cook
Over high heat, heat a cast-iron pan or another heavy pan until it smokes. Add the burgers, reduce the heat to medium-high and cook for four minutes per side or until they are almost at your desired degree of doneness.
Top the burgers with cheese and cover with a lid for one to two minutes or until the cheese is fully melted.
If the buns are too thick or too dense, pull a little bread from the center of the top half or slice a bit off from one of both of the cut sides.
While the patties are cooking, brush the buns with butter and toast them, cut side down, in a pan or on a grill until the cut side is lightly browned.
Spread the bottom bun with caramelized onions and the top bun with ketchup. Serve and enjoy!