Wash the chicken filet, dab dry and cut into cubes. Mix cumin, sweet paprika, coriander and pepper. Put chicken cubes in a bowl and rub with the spice mixture. Cover and put in a cool place for about 3 hours. Clean, wash and cut the zucchini into large cubes.
Peel and quarter the onion. Put chicken, onion and some courgette cubes on 2 skewers. Either grill skewers and zucchini cubes or put them in a lightly oiled or non-stick, ovenproof pan or dish. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 15-20 minutes