Rinse the red lentils thoroughly under running water until water runs clear. Drain well.

In a pressure cooker (or heavy pot), heat the oil over medium flame. Add cumin seeds and let them sizzle for a few seconds.

Add chopped onions. Sauté until they turn translucent (about 3–4 minutes). Then add minced garlic and grated ginger and sauté another 1 minute until fragrant.

Stir in chopped tomato and cook for 2 minutes until it softens slightly.

Add turmeric powder, cumin powder, coriander powder and red chili powder (if using). Mix well so the spices coat the onion-tomato mix.

Put the drained lentils into the cooker, pour in 4 cups of water and add salt. Stir gently.

Close the pressure cooker lid and cook for 2 whistles (or simmer in a pot for ~15–20 minutes until lentils soften). Once done, let the steam release naturally.

Open carefully and mash the lentils slightly with the back of a spoon for a creamy consistency. Add more water if needed to reach desired soup-like texture.

Check salt and spice. Pour into bowls, garnish with chopped coriander leaves and serve hot.