Cut the steak into 4cm chunks and transfer to a bowl; in a separate bowl mix together the spice powder, olive oil and thyme leaves; add most of the spiced oil to the steak, toss to coat, set aside for at least 20 minutes, or ideally a couple of hours
For the herb oil, crush the garlic with a pinch of salt; add the parsley, olive oil and grated parmesan, mix well, then thin with 2 tablespoons cold water; set aside
Separate each wedge of onion into petals; thread the steak onto 4 or 8 skewers, depending on the size, alternating with chunks of red pepper and onion, brush with the remaining spice oil over the red pepper and onion
Cook the skewers either on a barbeque or in a griddle pan for 8-10 minutes, turning every 2 minutes so that they cook evenly
Rest for 2-3 minutes before serving with the herb oil
4 servings