In a large pot, heat the olive oil over medium heat.

Sauté the chopped onion until it becomes translucent, about 5 minutes.

Stir in the minced garlic and cook for another minute until fragrant.

Add the diced sweet potatoes to the pot and stir for a couple of minutes.

Pour in the broth and add the ground cumin and ginger.

Bring the mixture to a boil, then reduce the heat and let it simmer for about 20 minutes.

Once the sweet potatoes are tender, use an immersion blender or transfer the soup to a regular blender. Blend until smooth.

If using, stir in the coconut milk and heat through.

Season with salt and pepper to taste before serving.