This is an easy hearty and satisfying soup with rich and aromatic spices, and coconut milk. Wonderful freshly made but it also holds up well and gets even better the next day, making it perfect for a make ahead meal.
In a large soup pot, heat the oil over medium-high heat. When hot, add the onion, garlic, and ginger. Suaté for about 5 minutes until the onions turn translucent and begin to brown.
Stir in the vegetable broth, diced tomatoes, brown or green lentils, curry powder, cumin, salt, and cayenne (if using). Cover and bring to a simmer. Cook for about 25 minutes until the tomatoes are cooked and the lentils are tender.
Stir in the coconut milk and heat through. Serve hot and garnish with cilantro.
If you would like to use red lentils, do not add them until the last 10 minutes of cooking so they don't get mushy.