Cook the poblanos and jalapenos under the broiler for about 5 minutes on each side or until thoroughly blackened. (The jalapenos will probably cook faster so remove them first) Place poblanos in a paper bag, close it and let them steam for 15 minutes. Meanwhile, remove stems from jalapenos and dice.
After 15 minutes, take the poblanos out of the bag and rub off the skin. Remove seeds and stem and then dice the chiles.
In a large pot, heat on medium the butter until it’s melted. Add the onions and cook them for 10 minutes or just until they’re about to brown. Throw in the garlic and cook for another minute.
Add to the pot the chiles, the potatoes, the chicken broth, the cilantro, the cumin, salt and black pepper. Bring to a boil and then simmer for 20 minutes or until the potatoes are tender.
Scoop out 2 cups of the soup and set aside. Puree the rest of the soup until smooth and then mix the smooth with the chunky. Add the milk and half and half to the soup and cook until warm. Squeeze in the lime juice and serve either warm or chilled, with cheese, tortilla chips and extra cilantro.