In a large pot, bring 5 cups of water to boil. Melt butter and add lentils. Cook for 15-20 minutes, until lentils are soft and water is mainly reduced.
Meanwhile, in a small bowl, combine red curry paste, coconut milk, salt, pepper, cayenne pepper, curry powder, chili powder, sugar, and lime juice. Mix thoroughly. When lentils are cooked, add coconut spice mixture to lentils. Mix well, taste, and adjust seasoning or lime as needed.
Serve lentils over rice with cilantro garnish.
Recipe by Things I Made Today at https://www.thingsimadetoday.com/2013/01/29/red-lentil-dhal-with-rice/