Preheat the broiler.

Place a large heavy skillet or griddle over medium-heat. Add the poblano chile pepper, onions, and garlic. Roast, turning occasionally, until nicely browned. The garlic will take 3 to 4 minutes; the pepper will take 6 to 8 minutes. Transfer to a plate to cool. Scrape as much skin off of the chile pepper as possible. (Use plastic gloves when handling). Finely chop the pepper, onions, and garlic.

In a large saucepan over medium heat, combine the peppers, onions, garlic, cumin, corn, the bay leaf, and stock. Bring to a simmer. Reduce the heat to medium-low and gently simmer for 8 to 10 minutes, or until the corn is soft. Remove and discard the bay leaf. Let cool slightly and then puree the soup in a blender; return it to the pan to rewarm again. Stir in the cilantro and cook for 1 minute. Season with salt and black pepper.

Ladle the soup into serving bowls and garnish each with a sprinkling of chili powder. Serve each with a lime wedge for squeezing into the soup.