Mince onion in a food processor. Place in a mixing bowl with other ingredients and season generously
Divide the meat into four equal portions and shape them into patties using a mold. We used square molds but round molds will work fine too.
Arrange the patties on a tray lined with parchment paper. To prevent oxidation, lightly brush the patties with olive oil. Next, cover the tray with plastic wrap and place it in the refrigerator for approximately 3 hours. This resting period will allow the flavors to harmonize and the burgers to firm up,