If using frozen peas, make sure they are thawed overnight. If you are using fresh peas, blanch them in a pot of boiling salted water for 5 minutes.
Heat oil on medium heat in a heavy bottom pot. Once oil is hot, add the sliced onions. Cook onions till they brown evenly. Strain the onions from the oil using a slotted spoon.You can reserve the oil used for frying the onions and use it in curries.
Add the onions to a small blender jar along with yogurt and kashmiri red chili powder. Blitz to make a smooth paste. Set aside
Warm up ghee in a cooking pot. Add the whole spices and crackle for 30 seconds.Next, add the ginger garlic paste and cook for 30 seconds or so till you smell a nice aroma. Add the powdered spices next, add 1 tablespoon water and sauté spices in oil for a minute.
Then add the tomato puree, sugar and salt. Cook for 3-4 minutes till you see oil seperating on the sides.
Stiring continously, next add the yogurt onion paste and now and cook again on medium heat till oil starts separating on sides.
Add blanched(or thawed) peas now and mix so that the peas are nicely coated in masala. At this point you can add few extra ginger juliennes as well. Sauté the peas with masala on low medium heat for 2-3 minutes so that they are warmed through.
Add the ⅓- ½ cup water next and mix everything. Let cook for 2-3 minutes till you see that the water is slowly bubbling. Add the crumbled khoya now. You will see that within a few minutes the khoya will melt and the sauce will appear to be milky. Keep the stove on low. Don't let come to a boil.
Let the curry simmer for 5 minutes on low heat till you see all the khoya has melted and its now part of the sauce. Switch off the stove and mix in the kasuri methi and garam masala. Add kewra if using.
Mix gently and let rest for 20 minutes before serving. Serve garnished with cilantro and ginger juliennes.