Warm the oil in a heavy saucepan over medium heat. Add the chorizo and cook it for 2 minutes, or until the fat begins to render.
Add the onion and garlic. Cook until the chorizo is well browned. Drain off the grease.
Add the tomato, chile and chicken stock. Bring the mixture to a simmer and slowly add cheese, blending it with a spoon. As each batch of cheese melts, add more, cooking over low heat. When the cheese has melted and the mixture comes together, it is ready to serve. Keep warm while serving.
(To roast poblano pepper: Lightly oil the surface of the pepper with vegetable or canola oil. Roast the pepper over a flame or under a broiler until it's charred on all sides. Set aside in a plastic bag for 10 minutes to allow the steam to loosen the skin from the pepper. Peel off the charred skin and discard it. Slit one side of the pepper down the middle, remove and discard the seeds.)
Servings: