Preheat your oven to 400°F (200°C). On a baking sheet, toss sweet potato wedges with olive oil, salt, and pepper until evenly coated. Spread them out in a single layer for even roasting. Bake for 25-30 minutes, turning halfway, until they are tender and caramelized.

In a large pot, heat a splash of olive oil over medium heat. Add the diced onion and sauté for about 5 minutes until softened and translucent. Stir in the minced garlic along with dried thyme, rosemary, and basil. Sauté for another 1-2 minutes until fragrant.

Add the roasted sweet potatoes to the pot, stirring them with the sautéed aromatics. Pour in the vegetable broth and bring to a gentle boil. Once boiling, reduce heat and simmer for 10-15 minutes.

Carefully blend the soup until it reaches a smooth, creamy consistency using an immersion blender. Adjust to texture preference.

Stir in coconut milk or heavy cream. Heat over low for an additional 5 minutes, adjusting seasoning with salt and pepper as needed.

Ladle the soup into bowls, garnishing with reserved sweet potato wedges and fresh herb sprigs if desired. Serve immediately.