Place ears of corn with husks onto a hot barbecue. Roast the corn in the husk for about 25 minutes, turning every 5 minutes. The outside of the husk will be a bit burned, that's OK. Carefully peel back the husk and inspect the corn. If there are some black spots, it's done. If you don't have a barbecue available, remove the husks and cook under a low broiler turning frequently. Allow the corn to cool. Remove the husks and silk, rinse with cool water, and cutoff the kernels.
Place the poblano peppers directly on the barbecue grill and cook until the skin has blackened (about 6-8 minutes). You can also cook the peppers directly over the flame on a gas range. Turn the peppers over and cook the other side. When the skin is blackened all the way around, remove the peppers and place them in a paper bag to cool (about 10 minutes). The paper bag allows the peppers to let off steam and loosen the skins. Don't use a plastic bag. The peppers are too hot and will melt the plastic.
When the peppers are cool, rinse them under cold water to remove the skins. Remove the stem and seeds. Cut into ½" pieces.
Heat 1 tablespoon of olive oil in a medium saucepan over medium-low heat. Add the onion and cook until softened, about 5 minutes. Add the garlic and the cumin and cook for one minute. Stir in the flour and cook for another minute while stirring constantly. Add the chicken stock and stir well. Add the corn kernels, diced poblano peppers and cilantro. Stir to combine. Cook 5 minutes to thicken.