Rinse 1 cup dried red kidney beans in a colander, then soak them in plenty of water overnight for at least 8 hours.

Drain the soaked red kidney beans and set them aside.

Dice 2 medium onions, 2 tomatoes, and 1 inch fresh ginger; slit 2 green chilies and finely slice the remaining small onion.

Heat 1 tbsp cooking oil in a large pot over medium heat, then add half the cumin seeds and half the coriander seeds.

Add the diced onions, 1 sprig curry leaves, diced ginger, slit green chilies, and salt; fry until the onions are golden brown.

Add the diced tomatoes and 1 heaped tsp tomato paste, then stir until the tomatoes begin to soften.

Stir in Kashmiri chili powder, paprika, turmeric powder, garam masala, coriander powder, and cumin powder.

Cook the spiced tomato mixture for 5 to 8 minutes, stirring regularly, until the oil starts to separate and the masala smells fragrant.

Add the drained red kidney beans and 2 cups water, then stir well to combine.

Cover and simmer the rajma until the beans are very tender, adding more water as needed to maintain a thick curry consistency.

Heat 1 tsp ghee in a small frying pan, then add the sliced onion, remaining curry leaves, remaining cumin seeds, and remaining coriander seeds.

Fry the tempering until the onion is golden and crisp, then pour it over the cooked rajma.

Garnish the rajma with coriander leaves leaves, then serve hot with cooked white rice and butter.