Heat a cast iron or heavy bottomed sauce pan over a medium heat and add all the spices to the pan. Let the spices toast in the pan for about 2 minutes. Add the olive oil and the thinly sliced garlic and remove from the heat. Drain the oil and spices into a small bowl and set aside.
To make the lentils, add another tablespoon of olive oil to the pan and start to cook the onions and sweet potato over a medium heat. When the onions and the sweet potato are are starting to soften add the lentils to the pan and cover with the water or vegetable broth.
Cook for about 15 minutes until the lentils are soft and the potatoes are cooked through.
Serve in a bowl or over rice and top with the tarka and the pomegranates and cilantro.