Preheat the broiler. Arrange the poblanos on a sheet pan, then position 4-6 inches under the broiler; cook until charred on all sides, turning every few minutes, about 8-12 minutes total. Transfer the poblanos to a bowl, cover tightly with plastic wrap. Let steam for 10 minutes the peel, seed and chop the peppers. Discard the skin, stems and seeds. Set aside. (Can do this one day before).
Add the ground beef to a large pot over medium-high heat. Cook stirring often, until the fat is rendered and the beef has begun to brown, about 8-10 minutes. Using a slotted spoon, remove and set aside, leaving the fat in the pan.
Add the leeks and cook, stirring occasionally about 5 minutes until softened. Add the minced garlic.
Add the chopped poblanos, corn, and oregano and continue to cook until the corn has cooked through, about 5 minutes. Add a little olive oil if mixture seems dry.
Add the chicken stock and cream cheese and simmer until the cheese melts and the flavors meld, about 5 minutes more.
Stir in the cream and the cooked ground beef.
Season to taste with salt and pepper.
Simmer until the soup is warmed through and serve at once.
Top with shredded monteray jack cheese before serving.