Cut chicken breast in medium sized kebab pieces. Transfer chicken pieces in a bowl and mix all the ingredients mentioned for marination with yogurt.
We need thick yogurt for this. Just keep the yogurt in a strainer for some time, this will drain off excess water and you will get thick creamy yogurt. Let chicken marinate for couple of hours.
Pre heat the oven at 200'C or 390 F.Put chicken pieces on a skewer, if not, simply put it in oven dish and place it in oven for 10-15 minutes. With this chicken tikkas are ready for the gravy.
For making gravy for chicken tikka masala, heat oil in a pan. When oil is hot add cumin seeds. When cumin seeds start to splutter, add finely chopped onion and split green chili. Let it cook till onions are slight golden brown in colour.
Add finely chopped tomatoes at this point. You can also make a paste of the tomatoes in blender and add if you like it that way.
In a small bowl, add coriander, red chili, turmeric and chicken tikka masala powder with little water and transfer this paste in the pan.
Let it cook for 2-3 minutes or till masala gets cooked, you will know masala is cooked when oil starts separating from masala. Add sugar and salt.
When masala is fully cooked add cream. You can also substitute cream with yogurt if you like. Slowly add yogurt in masala.
Add little water to make the gravy of the desired consistency. Wait for 3-4 minutes then add chicken tikka to it.
After a boil, garnish with chopped coriander. With this chicken tikka masala is ready. Serve with naan or rice.