Heat a large pot over medium heat and add a splash of oil. Add the diced onion and cook until translucent, about 5 minutes.
Stir in the minced garlic and freshly grated ginger, cooking for another 2 minutes.
Add the cubed sweet potatoes, curry powder, cumin, and paprika. Stir well to coat the sweet potatoes with the spices.
Pour in the vegetable broth and bring to a boil. Reduce the heat and let it simmer until the sweet potatoes are tender, about 15 minutes.
Stir in the peanut butter until it is well combined with the broth.
Add the coconut milk, salt, and black pepper. Let the mixture simmer for another 5 minutes.
Stir in the chopped spinach and cook until wilted, about 2 minutes.
Remove the pot from the heat and stir in the fresh lime juice.
Serve the curry with rice, garnished with fresh cilantro or peanuts.