1. 1 tablespoon of Plain yogurt can be added instead of sour cream
2. Adjust the water according to the consistency you wish. If you want it to be gravy add litlle more water. In tat case Onion - tomato masala can also be grinded and used for the curry
3.Heavy cream can be used instead of sour cream for richness
4.If you are using dry peas, cook it before adding it to the curry
5. I used vine tomatoes, if you are using osem other tomatoes adjust accordingly