Step 1Roast the poblano chiles over a gas flame using tongs, turning to blacken all sides, about 10 minutes. Or, place the chiles beneath the broiler. Set the chiles in a glass bowl and cover them with plastic wrap to steam, about 10 minutes. Discard the skin, stems and seeds and set the chiles aside.
Step 2Melt the butter in a large, heavy soup pot over medium heat. Cook the onion and garlic until they are soft, 6 to 8 minutes. Add the sweet potatoes, stock, chipotle chile and poblano chiles and cook at a simmer until the sweet potatoes are tender and the chiles are soft, about 30 to 35 minutes.
Step 3Remove the soup from the heat. Puree it with the honey and cream, in batches if necessary, until smooth. Season with salt and pepper to taste. Garnish the soup with cilantro leaves before serving.