Heat the olive oil in a large pot over medium heat.
Add the chopped onion and cook until translucent, about 5 minutes.
Add the garlic and ginger, and cook for another 2 minutes.
Stir in the curry powder, turmeric, and cumin, and cook for 1 minute.
Add the lentils, diced tomatoes, coconut milk, vegetable broth, and salt. Bring to a boil.
Reduce heat to low and simmer for 20-25 minutes, or until lentils are tender.
Stir in the chopped spinach and cook for another 5 minutes.
Serve hot with rice or naan.