If using flavorful thighs, trim the chicken pieces of fat. Cut all of the chicken into credit card sized pieces of roughly equal thickness (for even cooking).

Mix the dried spices together in a bowl, and then season all of the chicken pieces on both sides, rubbing in the spices so they adhere to the surface. It might seem like a lot of spices, but you won't regret it.

In a large bowl, whisk together the yogurt, olive oil, ginger paste, and garlic. Add the chicken to the bowl and coat the pieces thoroughly with the yogurt.* Cover the bowl and refrigerate for 3 to 4 hours (overnight is fine, too).

Heat the olive oil in a large skillet or braiser over medium heat, until the oil shimmers. Add the onions and sweat for 5 minutes. Scoot the onions to one side of the pan and pour a glug of oil in the open space,

Spoon the tomato paste, ginger, garlic, and dried spices over the oil, and mix into a dark, fragrant paste. Stir into the onions.

Pour in the tomato sauce, and mix well with the spiced onions, scraping up any flavorful bits from the bottom of the pan.

Increase heat as necessary to bring to a gentle simmer and cook for 15 minutes, covered, while you cook the chicken. (Technically, you don't need a lid to cook the sauce, but tomatoes splatter and will make a mess if you don't use a lid.)

Turn the broiler on high, and place a rack in the middle or upper middle position (about 7" or so from the heating units).

Line a large, rimmed baking sheet with foil (optional, for easy cleanup). Place the yogurt coated chicken pieces on the baking sheet in a single layer. If there's extra yogurt in the bowl, spread over any uncoated spots on the chicken. Discard the unused portion.

Broil the chicken for 8 to 12 minutes, or until brown spots appear on the yogurt. Keep an eye on things, don't just rely on the clock!

Flip all of the chicken pieces over, and broil for 5 minutes more. Remove from oven and let cool for a few minutes.

While the chicken cools a bit, reduce heat on the sauce to medium-low. Pour in the heavy cream or coconut milk and stir well.

When the chicken is handle-able, cut into bite-sized pieces and add to the sauce. (I usually don't wait - I hold one piece of chicken with tongs and use kitchen shears to cut it right over the sauce pan, letting the pieces fall into the sauce). If you notice that some of the chicken pieces have a bit of pink inside, don't worry: you can finish cooking the chicken in the sauce.

Let the chicken and sauce simmer gently together for another five minutes.

Top with cilantro and serve.