In a large pot, heat the oil over medium heat, then add the onion and garlic. Sauté until the onion is translucent.

Add in the chipotle peppers, adobo sauce, cumin, and sweet potato. Stir until fragrant (10 to 15 seconds).

Add the chicken stock and bring it to a boil. Then cover, lower the heat and let the soup simmer for 20 to 25 minutes, until the sweet potato is soft.

Purée the soup until smooth with a hand blender right in the pot, or in a countertop blender in batches, filling it no more than halfway and venting the lid so steam can escape.

Add salt and pepper to taste and garnish with cilantro or cream.