In a large pot or Dutch oven, heat the olive oil over medium high heat. Add the celery, carrot, onion, and garlic and sauté for 5 to 6 minutes until tender.
Add the sweet potatoes, water, lentils, cumin, curry powder, and kosher salt. Bring to a simmer and simmer for 25 to 30 minutes until the lentils are tender (if not tender, keep cooking a few more minutes). Add the spinach and coconut milk and stir until wilted, about 1 to 2 minutes. Taste and add additional salt to taste and fresh ground black pepper.
Serve immediately or refrigerate for meal prep. The soup lasts up to 1 week refrigerated and leftovers taste even better (you can also freeze them for up to 3 months). Leftovers may soak up extra broth, so you can add a splash of coconut milk and/or water and pinch of salt if the texture becomes too thick.
