1. Heat oil in a large saucepan over medium heat. Saute the onion until translucent (3-4 minutes), stirring frequently.
2. Increase the heat to medium-high. Stir in the cumin, curry powder, and cayenne. Cook until fragrant (30 seconds).
3. Stir in the tomatoes, potatoes, broth, lentils, and carrots. Bring to a boil. Reduce the heat and simmer, covered, until lentils are tender (30-40 minutes). Stir and add water as needed to keep from sticking.
4. Stir in the peas and simmer to heat. Remove from the heat and stir in parsley.