Melt 2 tablespoons of ghee/butter in a saute pan over medium heat.
Add the chopped potatoes and fry for 20 minutes, or until cooked through. Set aside for now.
Melt the remaining 1 tablespoon of ghee/butter to the pan and then add the cumin seeds. Once they brown, add the onion and serrano pepper and stir-fry for 3-4 minutes, or until the onions soften.
Add ginger, spices, stir-fry for a minute, then add the ground beef. Cook until the beef is browned and cooked through.
Add the peas and potatoes to the pan, stir for about 5 minutes, then garnish with cilantro and serve.