Heat 2 tablespoons of olive oil in a medium pot over medium heat. Add the chopped onions and sauté until translucent, about 5-7 minutes.

While the onions are cooking, rinse 1 cup of dry red lentils under cold water.

Add the rinsed lentils to the pot along with one can of diced tomatoes, 3 cups of water or vegetable broth, and all the spices. Stir until well combined.

Increase heat to bring the mixture to a gentle boil, stirring occasionally for 3-5 minutes.

Lower heat to a medium-low simmer, cover, and let cook for 10-15 minutes until lentils are tender.

Remove from heat and let sit covered for about 5 minutes.

Ladle into bowls and garnish with sour cream and fresh cilantro if desired.