Heat a tablespoon of oil in a large pan over medium heat until shimmering. Add the chopped onion and cook, stirring occasionally, until translucent and soft, about 5 minutes. You’ll notice the aroma sweetening and the onions turning a light golden.
Add the minced garlic and grated ginger to the pan, cooking for about 1 minute until fragrant. The mixture should sizzle gently, filling your kitchen with a warm, spicy aroma.
Stir in the ground cumin, coriander, turmeric, and chili powder. Toast the spices for about 30 seconds, stirring constantly, until they release their essential oils and become fragrant, turning the mixture a darker hue.
Add the rinsed red lentils to the pan, stirring to coat them in the spice mixture. Let them toast for a minute, absorbing the fragrant oils and starting to turn a slightly darker color.
Pour in the coconut milk and vegetable broth, stirring well to combine. Bring the mixture to a gentle simmer, watching as bubbles start to form around the edges.
Reduce the heat to low, cover the pan partially with a lid, and let it simmer gently for 20 to 25 minutes. Stir occasionally, and you'll see the lentils soften and break down, creating a thick, velvety sauce.
Once the lentils are tender and the sauce has thickened, remove the pan from heat. Squeeze in the fresh lemon juice, stir, and taste. Adjust the salt as needed to enhance the flavors.
Serve the curry hot, garnished generously with chopped cilantro. For extra richness, add a dollop of yogurt or a drizzle of coconut milk if desired. Enjoy this cozy, nourishing dish with rice or bread.