Ingredients :

• The grated onion — Not sliced, not coarsely chopped: grated. The difference is real. The onion juice penetrates directly into the chicken fibers and acts as a natural tenderizer. You get that melt-in-the-mouth texture at the heart of the cube that distinguishes an ordinary skewer from a memorable one. A classic yellow onion works perfectly.
• The plain yogurt — Optional according to the ingredient list, mandatory according to me. A tablespoon is enough. It creates a protective film around the chicken during cooking and helps the marinade stick well. Use full-fat yogurt—not 0%. Fat is useful here.
• The paprika — It provides the color: that deep orange-brown that makes you hungry before you even taste it. Avoid smoked paprika for this recipe; it would overpower the cumin. A mild supermarket paprika does the job just fine.
• The cumin — This is what gives it character. Slightly earthy, slightly bitter, it balances the freshness of the lemon. If you don’t have it, the skewer will be quite bland. There’s no truly equivalent substitute—it’s worth having in your cupboard.