Red lentils dissolve and thicken the pot while green ones stay whole, so nothing needs blending. Curry powder is toasted in coconut oil with onion, garlic and ginger, and full-fat coconut milk goes in at the end.
First, warm the coconut oil in a wide heavy pot over medium heat and cook the chopped onion for 6 to 8 minutes, until soft and translucent but not browned.
Next, add the garlic, ginger, curry powder, turmeric and red pepper flakes. Stir for a full minute, until the spices darken slightly and the kitchen smells of them. This step matters more than an extra spoonful of curry powder would.
Simmer the Lentils
Then tip in both lentils, the stock and the bay leaf. Bring it to a boil, drop it to a bare simmer, cover partly and cook for 30 minutes, stirring now and then so nothing catches on the bottom.
After that, check the lentils. The red ones should have vanished into the liquid and the green ones should be tender with no chalky center. Give them another 5 to 10 minutes if they are not there yet.
Finish and Serve
Fish out the bay leaf, then stir in the coconut milk and salt. Simmer uncovered for 5 minutes over low heat. Do not let it boil hard, or the coconut milk will split.
Finally, take the pot off the heat and stir in the lime juice and most of the cilantro. Taste and expect to want more salt and more lime. Ladle into bowls and scatter the rest of the cilantro over the top.
Notes
Lentils: use both kinds. Red lentils collapse and thicken the pot, green lentils hold their shape. Yellow split lentils replace red, brown replace green, and French green lentils want 10 extra minutes.No soaking is needed. Rinse until the water runs clear and pick over the green lentils for small stones.Coconut milk: full-fat, stirred in for the last 5 minutes only. A rolling boil splits it, and the light version tastes thin.Salt and acid go in late. Both slow lentils down, which is why the lime waits until the heat is off.Curry powder: a mild blend of turmeric, coriander and cumin. Madras blends are much hotter, so start with 2 teaspoons.Storage: 5 days refrigerated, 3 months frozen. It sets almost solid in the cold, so loosen it with stock when reheating.Nutrition values are an estimate.