- Add a swirl of oil to a medium pot. Heat over medium-high flame until shimmering. Add the onion, and sauté until slightly softened, 1 to 2 minutes. 
- Add the garlic and ginger, sautéing until fragrant and barely golden, about 1 minute. 
- Stir in the tomato paste. Add the curry, turmeric, red pepper flakes, and season with salt and pepper. 
- Stir in the coconut milk and vegetable broth. Add the lentils. Bring to a boil. Reduce flame to a simmer, and cooking until the lentils are very tender, and broken down, 25 to 30 minutes. The soup will be thick, and the lentils broken down a bit. Serve hot, topped with cilantro and a squeeze of lime. 
- Note for leftovers: The soup thickens as it cools, so you might want to add a little more coconut milk or broth when reheating.