Cut the chicken into 1.5-inch pieces. In a large bowl, mix 0.5 cup of the Greek yogurt with the lemon juice, half the garlic minced, half the ginger, 1 tablespoon of the garam masala, half the cumin, the paprika, half the turmeric, and half the salt. Add the chicken, coat well, and let it sit for 15 minutes while you start the sauce. Overnight in the fridge is even better.

Set an oven rack about 6 inches below the broiler and turn the broiler to high. Line a sheet pan with foil.

Heat the olive oil in a large deep skillet over medium heat. Add the onion and cook 5 to 6 minutes until soft and golden. Stir in the remaining garlic and ginger and cook 1 minute.

Add the remaining garam masala, cumin, turmeric, and salt. Stir for 30 seconds until the spices smell toasted, then pour in the tomato sauce and 0.5 cup of water. Simmer gently, uncovered, for 10 minutes, stirring now and then.

While the sauce simmers, spread the marinated chicken in a single layer on the sheet pan. Broil 4 minutes, flip, and broil 3 to 4 minutes more until charred at the edges and 165°F in the center.

Add the broiled chicken and any juices from the pan to the sauce. Simmer 2 minutes so the flavors come together.

Turn off the heat and let the pan sit for 1 minute. Stir a ladle of the hot sauce into the remaining 0.5 cup of Greek yogurt, then stir that mix back into the skillet until the sauce is smooth and creamy. Do not let it boil after this point.

Scatter the cilantro over the top and serve with basmati rice, naan, or steamed vegetables.