Chop onion finely, potatoes into small bite sized cubes and tomatoes roughly.In a small pressure cooker, add oil and splutter cumin seeds in medium heat. Add onion and fry till transparent. Add ginger garlic paste and fry in medium flame for a minute.
Add chopped potatoes and green peas, little salt. Mix well and cook covered in low flame for 2- 3 minutes.
Meanwhile puree the tomatoes in a blender/ mixie.
Mix the potatoes and peas in between once to avoid it getting burnt. Add the tomato puree and all the dry powders.Cook in medium flame, if you want you can cover, for 4 minutes or until the tomato puree becomes shiny.
Add a 1 & ¼ cup water and mix well. Add required salt, pressure cook for 2 whistles in medium flame. Once done, you can adjust the consistency of the gravy by adding more water or milk and just give one boil.