Heat up oil in a pot. Once hot, add cumin seeds, green cardamom, cloves, cinnamon stick, and bay leaf. Saute for 30 seconds.
Add onions and cook for 2 minutes or until translucent.
Now add tomatoes, garlic, ginger, green chilies, and salt. Stir well.
Now add Kashmiri red chili powder, turmeric powder, and coriander powder. Stir well.
Add 1 1/2 cups of water and cashews.
This is what you should have.
Cover and cook for 15 minutes on low heat.
Once done. Discard bay leaf. Add 2 tablespoons of butter and stir well. Let the mixture cool for 15 minutes before blending. While the mixture cools - grill the chicken. Go to the Grill Chicken section.
Once cooled, transfer the onion-tomato mixture to a blender.
Blend until smooth and creamy.