In cold water, rinse and drain rice several times. Place drained rice in medium saucepan with 3 cups fresh cold water. Bring to a boil. Cover and reduce heat to medium-low and cook for 45 minutes, or until water is fully absorbed. Some of the rice grains may sprout during cooking.

In large heavy saucepan, heat oil over medium heat. Add cumin and mustard seeds and sauté until they begin to pop, about 1 minute. Immediately add onion, ginger, turmeric, and ground cumin. Add a splash of water and sauté for about 3 minutes, or until onion is soft but not browned. Stir in diced tomatoes and their juices, 4 cups stock, lentils, and cinnamon stick and bring to a gentle boil. Cover, reduce heat, and simmer gently for 20 minutes. Stir occasionally, adding a little more stock for a thinner consistency. Stir in coconut cream for added richness if you wish. Cover and continue simmering for a few more minutes, or until piping hot. Remove cinnamon stick and stir in lime juice and maple syrup. Add salt and pepper to taste, if desired.

To serve, place scoops of black rice in individual serving bowls and ladle curried dahl overtop. Serve sprinkled with toppings of choice.