In a large pot, heat the oil on medium then add in 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 in the chicken stock and cover. Lower the heat to low and let the soup simmer covered for 20 to 25 minutes or until the sweet potato softens.
Pour soup into a blender (or use a hand blender) and purée until smooth.
Add salt and pepper to taste and garnish with cilantro or cream.