Add oil and ghee in a pan over medium heat.
Add the whole spices - cinnamon, cloves, peppercorns, cardamom, big cardamom, mace, star anise.
Add the onion chunks. Also add the asafoetida. Stir fry till they become a bit soft.
Add the garlic, ginger and green chilli. Stir fry for 2 minutes.
Add the cashew nuts. Stir fry for 2 minutes.
Add the tomato puree or chopped tomatoes.
Cover the pan and cook the mixture for 5 minutes.
Allow the mixture to cool down a bit.
Add the mixture and 1 cup water in a blender jar or jug.
Puree the mixture to a smooth consistency.
Return the sauce to the pan.
Return the pan to medium heat.
Add salt, sugar, cream and whisked yogurt.
Mix well. Lower the heat.
Keep stirring the sauce till it becomes hot.