Rinse and pat dry chicken breasts. Cut into medium-sized pieces.
In a large mixing bowl, add chicken pieces, ginger/garlic paste, garam masala, Tandoori masala, juice of one lemon, freshly ground black pepper, Kosher salt and mix well. Massage chicken pieces with spices (I wear cooking gloves when mixing). Cover with saran wrap and set aside for 30 minutes (in fridge or at room temperature).
Heat a wok or 'Kadai' on high heat. Add oil, turn heat to medium high and add sliced onions. Saute onions for 7-10 minutes until softened and slightly golden brown, mixing as needed. Add 2 chopped Roma tomatoes, mix well, saute for an additional 3-4 minutes on medium high heat. Turn heat to medium, cover wok and simmer onions/tomatoes mixture for 10-12 minutes, mixing as needed (maybe once or twice).
Now uncover wok, turn heat to medium high and add marinated chicken pieces. Carefully mix to combine all ingredients and let chicken cook for 7-10 minutes. Cover wok ('Kadai'), turn heat to medium low and cook chicken for 15 minutes. Now add sliced green peppers, mix well, turn heat to medium, partially cover wok (to allow for excess water to evaporate) and cook for an additional 10 minutes.
Preheat oven to 375 degrees Fahrenheit. Uncover pot, turn heat to medium high and evaporate excess water while chicken continues to cook through (approximately 5-6 minutes), mixing as needed. Once oil starts to separate, add ¾ cup whisked yogurt, mix well and cook for an additional 4-5 minutes. Turn off heat, add 1 tbsp ghee, freshly chopped coriander leaves and slit green chillies. Place wok/'Kadai' in preheated oven and bake chicken, uncovered for 15 minutes. Done. Carefully remove from oven and let rest for 5-7 minutes.
Marvelously delicious Chicken Kadai is now ready to serve. Tastes sublime with plain Basmati rice or homemade parathas. Enjoy! Nosh Farma'aiye.