Measure all burger ingredients (minus the buns) into a medium sized bowl.
Use your hands to mix together the burger ingredients. Make sure to break up any large pieces of ground beef but be careful not to overmix.
Split the meat mixture into 4 equal parts and lightly flatten each until they are about 4 inches in diameter.
Place the patties on the parchment paper, then use a couple of fingers to gently make a small crater in the center of each patty. This little dip in the meat will stop the burgers from ballooning out when cooked.
Gently cover the burgers and move them to the fridge for about 30 minutes.
Meanwhile, pre-heat your grill to medium high heat. Be sure to clean your grill before adding the burgers, in order to prevent them from sticking. If you don't have the ability or willpower to clean the grates, apply a light layer of oil to them just before starting the burgers.
Move the patties to the grill and cook them for 4-5 minutes per side, until they've reached your preferred doneness.
If desired, toast the buns on the coolest part of the grill for about 30 seconds. A little olive oil or butter applied just before grilling will make for the best grill marks.
Spread aioli on the burger buns, if desired, and add any chosen toppings to your burgers before serving.