Make a thick paste using cilantro, ginger and garlic.
Add the paste to the chicken along with yogurt, turmeric powder, kasuri methi, tandoori chicken masala, lemon juice and salt.
Mix well and refrigerate for at least 30 minutes.
Bring a large pot of lightly salted water to a boil.
Add spinach and blanch for 3 minutes.
Switch off the heat and leave the spinach in the hot water for 2 minutes.
Drain and immediately transfer the spinach to cold water.
Drain again.
Blend the spinach with 1 teaspoon chopped garlic and 1 teaspoon chopped tomato until smooth.
Heat oil in a kadai or large skillet.
Add chopped onions and sauté until soft and lightly pink.
Add sliced garlic and sauté until fragrant.
Add ginger-garlic paste and green chilies. Sauté for 1 minute.
Add turmeric powder, red chili powder, cumin powder and coriander powder.
Add chopped tomatoes and cook until soft and mushy.
Add the marinated chicken and mix well.
Cover and cook until the chicken is about 50% cooked.
Add the spinach puree and mix well.
Continue cooking until the chicken is completely cooked.
Add kasuri methi and garam masala.
Add fresh cream and mix.
Adjust salt to taste.
Serve hot with naan, roti, bread or Jeera Rice.