Finely slice the onion and fry in oil and butter on a very high heat. If the meat is very lean use a good slab of butter. Let the onions brown at the edges but not in the middle.
Just before the onion is fully cooked at the garlic, finely chopped, and fry until onions complete.
Remove from heat and frying pan and let them cool.
Combine ground beef, onions, garlic, capers, mustard, parsley and pickle.
Gently work together and form into four hamburger patties.
Season with salt and pepper.
Place patties on preheated grill and grill until done over a high heat (about 5 minutes).
