Begin by rinsing one cup of red lentils under cold water until the water runs clear, then set aside to drain.
Heat two tablespoons of oil in a medium-sized pot over medium heat until it shimmers and begins to warm.
Add the finely chopped onion to the hot oil and sauté for about 5-7 minutes, stirring occasionally, until the onion turns golden and fragrant.
Stir in the minced garlic and cook for another minute until it becomes aromatic and fragrant, filling the kitchen with a warm aroma.
Add the cumin, turmeric, and coriander directly to the pan, stirring constantly for about 30 seconds to toast the spices and release their fragrant oils.
Pour in the chopped tomatoes and cook for 3-4 minutes, stirring occasionally, until they soften and start to break down, releasing a bright aroma.
Add the drained lentils to the pot along with three cups of water or broth. Stir well to combine all the ingredients.
Bring the mixture to a boil over high heat, then reduce the heat to low, and partially cover the pot. Let it simmer gently for 20-25 minutes, stirring occasionally, until the lentils are soft and have broken down into a creamy consistency.
If the curry thickens too much before the lentils are fully cooked, add a splash more water. If it's too thin after simmering, uncover and cook for a few more minutes to thicken.
Stir in the coconut milk and cook for another 2-3 minutes, allowing the flavors to meld and the curry to become rich and velvety.
Turn off the heat and squeeze in the lemon juice, stirring gently to brighten the flavors. Let the curry sit for 5 minutes to allow the flavors to develop further.
Serve the hot lentil curry with rice or flatbread, garnished with fresh herbs if desired, and enjoy the comforting aroma and creamy texture.
