In a pot, sautee the onions in a few tablespoons of olive oil over heat until translucent. Add the sweet potato and and the lentils and stir to cover with oil. Add the spice combo and just enough water to cover. Bring the water to a boil and then reduce the heat and allow the mixture to simmer until the potatoes and lentils are soft, about a half hour. Stir occasionally ; you may need to add a little water as you go. When the potatoes and lentils are soft, remove about half of them into a bowl and mash them with the back of a fork. Put them back into the pot along with almost all the cilantro. Stir and allow to cook for about 5 or 10 more minutes.
Serve in bowls with the rest of the cilantro sprinkled over the top.
If you wanted it to be a heartier meal, serve over brown rice.