Pre-heat the oven to 400. Line a baking sheet with aluminum foil. Brush the outsides of the poblano and red peppers with the olive oil and set them on the baking sheet. Pleace in the oven to roast for about 30 minutes until the skin on the peppers is charred and peels off easily. Peel the skins off the peppers and slice them open to discard the seeds. Chop the peppers into small pieces and set aside.

In a large pot, melt the butter over medium-high heat. Add the garlic, onion and celery and cook for about 5 minutes until the onions are translucent. Reduce the heat to low and stir in the flour to coat the vegetables. Cook for another five minutes, stirring frequently. Turn the heat back up to high and slowly whisk in the vegetable broth, stirring constantly. Add the milk and stir to combine. Bring the soup to a boil and then reduce heat to simmer for 5 minutes, stirring often. Add the poblanos, red pepper, potatoes, and corn. Simmer uncovered for 30 minutes. Add the cayenne, salt & pepper and stir.

Transfer three cups of the soup mixture into a blender and blend until the potatoes, corn, etc are smooth and the mixture is thick. Pour the thickened mixture back into the pot with the rest of the soup and stir to combine. Simmer for an additional 5-10 minutes and serve.