2 x 225g thick sirloin steak, cut into 3cm cubes
1/2 large red onion, cut into 3cm pieces
1/2 small orange pepper, cut into 3cm pieces
1/2 small courgette, cut into 2cm thick rounds
2 large button mushrooms, cut in half
4 x 25cm wooden skewers, soaked in water for 20 minutes