Heat the oil in a 4 quart saucepan over med-high heat. Saute the cumin seed for 1 minute.
Add 4 cups of water and 1 tsp of the salt, black pepper, lentils and rice and stir.
Bring to boil, cover and reduce heat to simmer for 40 minutes. (If not all of the water is absorbed after this time and the lentils and rice are cooked, remove the lid, and boil for a few minutes until the water is evaporated). Turn off heat and keep covered for 5 minutes.
While the rice and lentils are cooking, heat a large saucepan over medium high heat.
Saute the sliced onions with a few tablespoons of oil and ¾ tsp salt for 10 minutes stirring frequently and then reduce to medium-low heat and continue sauteeing until tender and caramelized, stirring periodically for 15 minutes or more.
Combine half of the onions with the rice and lentils.
Season to taste with salt and pepper. Serve topped with the remaining onions. Garnish with fresh mint or cilantro