Blend yogurt, tomatoes, ginger, besan, curry powder and salt along with 1 cup of water to form a smooth sauce.
Heat 2tbsp oil in a large sauté pan, add the tempering ingredients and once the seeds start to splutter, take the pan off the heat and add 1 cup of water and the curry sauce.
Put the pan back on heat and bring the sauce to a simmer on medium heat. Reduce the flame to very low, cover and gently simmer for 15 minutes, stirring occasionally.
Add the boiled eggs and cook until heated through. Serve with rice.