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, 20-25 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 fresh cilantro if desired.
Notes
Stir frequently, especially in last 10 minutes—red lentils break down quickly and scorch easily on bottom
Don't skip rinsing lentils—removes starch and prevents foaming
For smoother texture, mash lentils with back of spoon before serving
If curry gets too thick during cooking, add water 2 tablespoons at a time
Full-fat coconut milk is essential for creamy texture—lite won't work the same