Boil the tomatoes for 10 minutes in 1 cup water and switch off the gas.
After cooling, add this to a mixer along with chopped onion and grind to a thin puree.
Heat the same pan in which the chicken tikkas were fried.
Add 1 teaspoon oil and 2 tablespoon butter. After the butter melts, add ginger and green chilies and sauté for 2 minutes.
Add the spice powders (turmeric powder, red chili powder, cumin powder and coriander powder) one by one and sauté till they mix well and are aromatic.
Now pour the tomato and onion puree and mix well with spices.
Simmer on low flame till oil rises to the surface of the gravy and the color of the gravy changes.
Add the chicken tikka pieces and mix well.
Add 1/2 teaspoon sugar and mix well.
Simmer the gravy for 10 minutes.
Add fresh cream and tandoori mayo, mix and simmer for 5 minutes.
Adjust salt to taste.
Garnish with cream, a knob of butter and coriander leaves.