In a large saucepan or Dutch oven, combine lentils, coconut milk, water, turmeric, cumin, garam masala, chili powder, garlic powder, and salt. Stir well.
Bring to a simmer over medium heat, stirring occasionally, about 5 minutes.
Reduce heat to medium-low. Cook, stirring frequently to prevent sticking and scorching, until lentils are completely tender and broken down and curry has thickened, 20 to 25 minutes. Mixture should be creamy and spoonable, not soupy.
Taste and adjust salt and chili powder as needed.
Serve over rice with lime wedges and cilantro leaves.
Notes
Stir often in the last 10 minutes, since red lentils break down fast and catch on the bottom.
If it gets too thick while cooking, add water 2 tablespoons at a time.
Use full-fat coconut milk. Light coconut milk makes a thinner curry.
To freezer prep, add everything except the water to a freezer bag, press flat and freeze. Cook from frozen in a pot with 1 cup water over medium heat, stirring often.
Keeps 4 days in the fridge or 3 months in the freezer. It thickens as it sits, so loosen with water when reheating.