Step 1

In a blender, combine half the yogurt, the garlic, chopped onion, ginger, oil, paprika, garam masala, cayenne, 1¼ teaspoons salt and 1 teaspoon black pepper. Puree until smooth, about 1 minute, scraping the jar as needed. Transfer 2 tablespoons of the puree to a small bowl and stir in the remaining yogurt. Cover and refrigerate until ready to serve. Scrape the remaining puree into a medium bowl, add the chicken and stir to coat. Cover and refrigerate for at least 30 minutes or up to 4 hours.

Step 2

Heat the broiler with a rack about 4 inches from the element. Line a rimmed baking sheet with foil, set a wire rack in the baking sheet and mist it with cooking spray. Thread the chicken onto 4 to 6 metal skewers, scraping off excess marinade, and place on the prepared rack.

Step 3

Broil until charred on the surface, 4 to 5 minutes. Remove the baking sheet from the oven, flip the skewers and continue to broil until well charred on the second sides and the chicken is just cooked through, 6 to 7 minutes. Serve the skewers with the yogurt sauce and sliced onion.