Heat a large soup pot or Dutch oven over medium heat.
Sauté the onion, garlic and ginger either in a small splash of oil (or dry sauté for an oil-free soup). Add the rest of the ingredients.
Simmer on low heat for 11-15 minutes, uncovered, until the lentils are cooked and tender. Do not boil the coconut milk, as it is delicate and can burn or curdle when boiled. Garnish with fresh cilantro and serve.
Pressure Cooker
Reduce the liquid to 3 cups instead of 4. Add everything except for the coconut milk and pressure cook on Manual (high) for 3 minutes. Use quick release. Stir in the coconut milk. Garnish and serve.