Marinate the chicken:
Place the chicken breasts on a large sheet of plastic wrap,
spacing them apart from one another, then cover with a second large
sheet of plastic wrap. Using meat mallet or a
rolling pin, beat the chicken until the breasts are an even ½ inch thickness.
In a small bowl, whisk together the yogurt, 1 tablespoon olive oil, lemon juice, and garlic. Add the chicken & rub
the marinade over the meat. Set the chicken aside while you make the
sauce.
Make the sauce:
In a small bowl, whisk together the Garam Masala, cumin,
nutmeg, paprika, cayenne, and ground ginger. In a heavy, wide sauté pan over medium high heat, melt the butter. Add
the onion and sauté, stirring occasionally, until light brown and
caramelized, about 5 minutes. (Note that because they are sautéed so
quickly over moderately high heat, the onions will not caramelize
evenly.) Reduce the heat to moderate then stir in the spice mixture. Add the tomato purée, water, heavy cream, and salt, and bring
the sauce to a boil. Reduce the heat to gently simmer the sauce,
uncovered, until thickened slightly, about 10 minutes. DO AHEAD: The sauce can be prepared ahead and refrigerated, in an airtight container, up to 3 days.
While sauce is simmering, cook chicken:
Heat a heavy 12inch skillet over
medium high heat until very hot and add ½ tablespoon of olive
oil. Working in two batches, cook the chicken breasts, turning them a
few times and lowering the heat if the chicken chars too quickly, until
just cooked through and browned well on both sides, 6 to 8 minutes
total. Transfer the chicken as cooked to a cutting board. Wipe the
griddle or skillet clean with a paper towel and cook the remaining
chicken, adding the remaining ½ tablespoon olive oil between batches.
When all the chicken is cooked, cut it into 1 1/2-inch
pieces. Add the chicken to the simmering sauce and continue to gently
simmer it, stirring occasionally, for 5 minutes. Remove the pan from the
heat, stir in the black pepper and chopped cilantro, and season with
salt. DO AHEAD: Chicken tikka masala can be prepared ahead, cooled, uncovered, and refrigerated, covered, up to 3 days.
To serve:
Transfer the chicken to a serving dish. Serve with naan, and/or if desired with rice.