Cook the onions: Heat a skillet over medium heat. Add a teaspoon of oil and the diced onion. Cook for 5 minutes, not stirring. Stir the onions, add a touch of water, and cook for another 5-6 minutes until browned. Add the garlic and cook for 30-60 seconds. Remove from heat and allow to cool.
In a small bowl, whisk the mayo, curry powder, Dijon mustard, and vinegar. Add the cooled onion and garlic and stir to combine.
For the Burgers
Combine all of the burger patty ingredients in a bowl and mix well. Divide into 4 portions and form each portion into a burger patty. Leave an indent in the middle so the burgers cook flat.
Cook the burgers: In a grill pan: cook the patties in a preheated grill pan over medium heat for 5-7 minutes per side or until cooked to an internal temperature of 160°F (71°C).On a grill/BBQ: cook the patties on a preheated grill over medium-high heat, for 4-5 minutes per side, turning once, or until cooked to an internal temperature of 160°F (71°C).
Toast the hamburger buns for 2-3 minutes.
To serve the burger, add the curry sauce to the bottom bun, followed by the burger patty and cilantro. Add sauce tot he top bun and add it on top of the cilantro to close the burger. Serve hot.
Video
Notes
For juicy burgers avoid pressing down on them with a spatula or poking them open. This releases their moisture and can result in dry burgers.The nutrition estimate doesn't include buns as that can vary greatly.