Combine the ground lamb with the grated onion, three minced garlic cloves, four tablespoons of chopped mint, ground coriander, and Dijon mustard in a bowl.
Make 4 burger patties from the mixture, then put them in the fridge to chill.
Combine the remaining tablespoon of chopped mint, parsley, and dill with the mayonnaise, lemon juice, the remaining two minced garlic cloves, a pinch of paprika, and the contents of a clean bowl.
Put this sauce in the fridge until you’re ready to use it.
Turn the grill to high, brush the lamb patties with a little oil, and cook for about 4 minutes on each side.
Split the burger buns in half lengthwise and toast them for 30 seconds to 1 minute.
Spread some of the mayonnaise sauce on the bun, place a burger patty on top, add some red onion slices, more mayonnaise sauce, and finally some salad leaves.
Serve and enjoy.