1/4 cup freshly grated Cotija or Pecorino Romano cheese
3 tablespoons raisins, chopped
4 large poblanos (1 1/2 pounds)
1/2 cup shredded Cheddar cheese
1/4 cup sour cream
2 tablespoons milk
1 tablespoon chopped cilantro
1/2 tablespoon fresh lime juice
Preheat the broiler. Position a rack 8 inches from the heat. In a skillet, heat 1 tablespoon of oil until shimmering. Add the onion and garlic; cook over high heat until softened. Add the pork, beef, cumin, coriander, oregano and cayenne and stir until the meat is no longer pink, 7 minutes. Season with salt. Stir in the sunflower seeds, Cotija and raisins.
Rub the poblanos with oil and broil, turning occasionally, until charred all over, 7 minutes. Transfer to a plate, let cool slightly, then peel. Slit the chiles along 1 side. Using scissors, snip out the cores. Scoop out the seeds. Fill the chiles with the meat mixture, sprinkle with the Cheddar and broil until the cheese is golden. Transfer to plates.
In a bowl, blend the sour cream, milk, cilantro and lime juice. Season with salt, spoon over the poblanos and serve.