Cut the rump steak into square slices, 5 mm (¼ inch) thick.
For the marinade, peel the garlic and chop it finely. Combine the garlic with the tomato sauce, meat extract, olive oil and pepper.
Place the steak in the marinade and chill for 3 hours. Cut the prawns in two. Assemble the skewers, alternating prawns and beef, and cook them over high heat for 7–8 minutes.