Squeeze some of the liquid out of the grated zucchini.
Combine all of the meatball ingredients in a large bowl, except for the olive oil or butter. Mix together very well and form into 12 patties.
Heat 2 tbsp of olive oil or butter in a large frypan over a low heat and gently fry the burgers in batches for about 10 minutes on each side, until cooked through and lightly browned. Add more olive oil or butter as needed.
Meanwhile, make the sauce by stirring all of the ingredients together in a small bowl.
Serve the patties warm or at room temperature with a salad and the sauce on the side.
Roll the patties in sesame seeds before cooking them.
Make burgers by wrapping a patty in a large lettuce leaf with sliced avocado, sauerkraut and the yoghurt sumac sauce.
Serve the patties with tatziki instead of minted sumac yoghurt.
You can leave out the chilli flakes or cayenne pepper if cooking for kids.
Make a double batch of patties and freeze some. They defrost very well.