Wash the lentils in cold water until the water runs clear and set aside.
Heat olive oil in a large Dutch oven or heavy bottomed pot over medium heat, add onions, garlic, and ginger and cook until soft and translucent, about 3-5 minutes. Add curry paste, curry powder, turmeric, cumin and salt and mix together until the onions are well coated and fragrant.
Add the red lentils, sweet potatoes, and vegetable broth. Bring mixture to a boil, then cover and simmer until sweet potatoes are knife tender and red lentils are cooked and thickened, 35-40 minutes. Season to taste with salt and pepper.
Serve with fresh cilantro, lime wedges, and yogurt.
Notes
Storage: Store any leftovers in an airtight container. They will last about 4-5 days in the fridge.Freezing Instructions: This curry freezes really well for up to 3 months. Thaw in the fridge overnight and reheat in the microwave or on the stovetop.Sourcing: I kept the spices pretty standard, so you can find them wherever you generally buy spices.Substitutes: For best results, follow the recipe as is. However here are some common substitutes that would work well in this recipe.
Instead of red lentils, you can use green lentils. Red lentils are typically used in Indian cuisine since they break down more easily than green lentils and are great for thickening curry.
Feel free to skip some spices or add other popular Indian spices like garam masala, ginger or cardamom.
If you don't want to use sweet potatoes, you can use white potatoes or add other vegetables like peas, carrots or cauliflower.