Heat the olive oil in a large, heavy-bottomed soup pot over medium heat. Add the onion and garlic and cook, stirring frequently, for 5–6 minutes, until softened and lightly golden.
Add the vegetable broth, sweet potatoes, and salt. Increase the heat to high and bring to a boil. Reduce the heat, cover, and simmer for about 15 minutes, stirring occasionally, until the sweet potatoes are very tender and easily pierced with a fork.
Stir in the coconut milk and sunflower seed butter. Using an immersion blender, purée until completely smooth. Alternatively, carefully blend in batches in a countertop blender. Return the soup to the pot and warm gently over low heat. Avoid boiling.
Ladle into bowls and top with sunflower seeds and a scoop of cooked quinoa for extra plant-based protein. Finish with a squeeze of fresh lime or lemon juice andadjust the salt to taste.
