In a large bowl mix together the mince, garlic, tomato ketchup, mustard, egg, chilli and onion.
Dive in with your hands and mix until the ingredients are well blended.
Just before cooking, add the spring onions and basil to the mixture and divide into four patties.
Heat a little olive oil in a large non-stick frying pan and fry the burgers.
Turn them once only, cooking for about 5-6 minutes each side. (Alternatively you can cook them under a grill for the same time turning half way through.)
Serve with burger buns and salad.