Soak the skewers in water for 30 minutes.
Cut the chicken breast into cubes (about 1 inch).
Grate the garlic and add it to the chicken.
Add salt, pepper and the optional seasoning cube.
Add vinegar and oil.
Finely chop the parsley and add it to the chicken.
Let it marinade for 15 minutes.
Cut the onion into squares
Put the onion on the skewers followed by the chicken
Cook on an electric grill or barbecue for 12 to 15 minutes while turning.
When it is ready, add the tomatoes on top.
Serve with your favorite side dish.