Heat some oil in a large pot over medium heat. Add the chopped onion and garlic and sauté until fragrant.
Add the diced sweet potatoes to the pot and cook for a few minutes until they start to soften.
Stir in the curry powder, cumin, coriander, turmeric, salt, and pepper. Mix well to coat the sweet potatoes.
Pour in the coconut milk and diced tomatoes. Bring the mixture to a simmer and let it cook for about 15-20 minutes until the sweet potatoes are tender.
Add the butter beans to the pot and stir gently to combine. Cook for another 5 minutes to heat the beans through.
Taste and adjust seasoning as needed. If the curry is too thick, you can add a bit of water or more coconut milk.
Serve the Sweet Potato & Butter Bean Curry hot, garnished with fresh cilantro. Enjoy with warm naan bread on the side.
