Soak bamboo skewers in water.
Peel, Devein and wash prawns.
Pat dry with paper towels.
Preheat the BBQ or frying pan to medium-high heat.
In a large bowl, toss prawns, beef, zucchini, and capsicum with olive oil, salt, and pepper.
Thread the marinated ingredients onto skewers, alternating between prawns, beef, zucchini, and capsicum.
Cook the skewers on the preheated BBQ or frying pan for 5-7 minutes, or until the prawns are pink and the beef is cooked to your liking.
In a small bowl, combine melted garlic butter with additional salt and pepper to taste.
Brush the skewers with the garlic butter sauce before serving.