If using dried kidney beans, soak them in water overnight. Drain and rinse them before cooking. Pressure cook the soaked beans with enough water and a pinch of salt for 15-20 minutes until soft. If using canned beans, rinse and drain well. Set aside.

Heat oil or ghee in a large pan over medium heat. Add cumin seeds and allow them to sizzle until fragrant. Add the minced garlic, grated ginger, and green chilies. Sauté for 1-2 minutes, stirring occasionally.

Add finely chopped onions and sauté until they turn golden brown, about 5-7 minutes. Ensure even browning by stirring frequently. The caramelized onions provide a rich base for the curry.

Stir in the pureed tomatoes and cook for 5-7 minutes until the oil separates from the tomato mixture. This step helps reduce the acidity of the tomatoes, creating a balanced flavour.

Add turmeric, coriander, red chili powder, and salt. Stir the spices into the tomato-onion mixture and cook for another 2-3 minutes to bring out the flavors of the spices.

Add the cooked kidney beans and their cooking water (or 1 ½ cups water if using canned beans). Stir well, ensuring the beans are coated in the spiced mixture. Let the curry simmer on low heat for 15-20 minutes, stirring occasionally. This allows the beans to absorb the spices.

Add garam masala and adjust salt to taste. Let the curry simmer for another 5 minutes. For a thicker consistency, you can mash some of the beans with the back of a spoon.

Garnish the rajma with fresh cilantro leaves and serve with steamed rice or roti. Add a lemon wedge on the side to enhance the flavors with a hint of acidity.