Marinate the chicken:

1. Preheat oven to 375 degrees. In a medium sized bowl, combine Greek yogurt and chickpea flour. Beat with a fork until well blended and smooth. Add in the garlic, ginger, chili powder, coriander, 1/2 teaspoon cumin, garam masala, and turmeric. Mix thoroughly.
2. Place chicken in the marinade and chill in refrigerator for 4 to 6 hours, or overnight. Return to room temperature before cooking.
3. Remove chicken from marinade (reserve remaining marinade) and bake chicken pieces in oven for 10 minutes. Baste chicken with reserved marinade and bake another 10 minutes until pieces are done. Transfer chicken to a dish, cut into bite sized pieces and set aside.

Make the tikka masala:

1. Melt the oil in a large skillet or wok with a lid over medium heat. Add the garlic and chili pepper and stir-fry for 1 minute. Stir in remaining cumin, paprika, and salt & pepper to taste and continue stirring for about 30 seconds.
2. Stir in the tomatoes and cream into the skillet. Reduce the heat to low and let the sauce simmer for about 10 minutes, stirring frequently, until the liquid reduces and thickens.
3. Add the chicken pieces to the skillet, cover, and let simmer for 3 to 5 minutes, until the chicken is heated through. Garnish with cilantro and cashew nuts, and serve on a bed of basmati rice, with Naan bread for dipping.