Add lentils to a pot, cover with water and simmer over medium heat until tender, about 20 minutes.

While lentils are simmering, heat oil in a large pot over high heat with mustard, cumin and fenugreek seeds. Cover pot and heat until mustard seeds complete popping sounds. Quickly add chile pepper. Let chile roast in the hot oil, then add onions, garlic and ginger. Remove chile, if desired.

Lower heat to medium and stir well. Let onions become translucent; add turmeric, coriander, cumin and paprika. Stir well and let spices release their essence into the oil. Take care not to let them burn (if needed, add more oil to prevent burning). Add fennel bulb and sauté for a few minutes.

Add tomatoes, cilantro stems (reserve leaves for garnish) and lemon juice. Allow tomatoes to reduce down and form a paste with onions. This will take a few minutes and will form the base of your curry. Season with salt. It’s important you don’t leave the stove. Watch the pot for signs of burning and constantly stir the mixture. If the mixture starts to dry out, add small amounts of water.

When the mixture reaches a thick consistency and a dark red color, add cooked lentils. Stir well, letting lentils incorporate into the curry base. At this point add kidney beans. For a soupier consistency, add more water.