Place wooden skewers in cold water. Peel and finely chop the onion. Mix with oil, cayenne pepper and cumin. Wash the fillet, dab dry, cut into coarse cubes and place on the skewers.
Brush with the spice oil.
Heat a coated pan without fat. Fry the skewers in it all around for about 8 minutes.
Coarsely chop the peanuts. Wash the mint, shake dry and cut into thin strips, except for a little to garnish. Mix yoghurt, nuts and mint. Season to taste with salt and pepper.
Season skewers with salt. Serve with yoghurt sauce and garnish with mint. Flat bread goes well with it.