Heat the olive oil in a large pot over medium heat. Add the onion, garlic, and ginger and cook for 4 minutes until the onion softens.
Stir in the ground coriander and curry powder and cook for 1 minute until the spices smell fragrant.
Add the lentils, diced tomatoes with their juices, and vegetable broth. Bring the mixture to a boil.
Reduce the heat to low, cover the pot, and simmer for 25 minutes until the lentils are tender.
Season with salt and black pepper to taste before serving.