In a large bowl mix together the brown sugar, Worcestershire sauce, ketchup, mustard, salt, pepper and egg.
In a frying pan, over low heat add the olive oil. When hot, add the onion and sauté for 5-7 min until soft and translucent, but not browned - stiring occassionaly. Add the minced garlic and sauté for another minute or so. Set aside to cool a bit.
Once onion/garlic mixture has cooled, add to the bowl with the egg mixture, stir to combine.
Add freshly grated parmesan cheese, stirring to combine.
Add ground beef and stir to incorporate mixture evenly, but try to handle the meat as little as possible – the more you work it, the tougher it gets.
Shape into 4-6 balls, and flatten each into a patty with your hand or a burger press. Then place place a slight depression (thumbprint) into the centre of each patty to prevent the burgers from puffing up on the grill.
Burgers may also be made ahead to the point, covered and kept in the fridge until the following day.
When ready to cook - Take burgers out of fridge and let sit a room temperature for 10 minutes.
Preheat BBQ or cast iron grill to medium high (approximately 375*F).
Place burgers on grill and cook for 4 minutes, lower heat to medium and flip the burgers cooking for 5 additional minutes. The internal temperature of the burgers should be 160*F when removed from the grill.