1. Take 20 skewers and soak them in cold water for 10 minutes.
  2. To make the marinade, place the oil, onion, garlic, tomato, basil and lemon into a food processor or blender and blend until a paste forms.
  3. Skewer 4 prawns onto each skewer until all skewers are filled.
  4. Using a pastry brush, coat each skewer with the marinate until all are fully covered.
  5. Cook in a non-stick frypan for 2 minutes on each side.