In a bowl, combine beef, onion, garlic powder, salt and pepper.
Form into 4 burger patties.
Cook on a grill or skillet for 4–5 minutes per side.
Mix all sauce ingredients together.
Assemble burgers using iceberg lettuce leaves as the bun.
Top with avocado, pickles, onion and sauce.
Serve with a simple romaine, cucumber and tomato salad.
