Queso Fundido Burger
2 fresh medium poblano chiles
1 medium onion, sliced into 1/4-inch slices
2 cloves garlic, minced
2 teaspoons oil
1 1/2 pounds ground chuck
8 ounces chorizo, cooked
1 to 2 canned chipotle chiles den adobo, finely minced, seeded if you wish
8 thick slices Monterey Jack cheese
4 hamburger buns, lightly toasted
Roast the poblanos over an open flame or 4 inches below a broiler, turning regularly until blistered and blackened all over, about 5 minutes for an open flame, 10 minutes for the broiler. Place in a bowl, cover with a kitchen towel and let cool. Rub off the blackened skin and pull out the stems and seed pods. Cut into 1/4-inch strips.
Heat the oil in a medium skillet over medium. Once the oil is hot, add the onions, stirring frequently until it begins to brown, 7 to 8 minutes. Stir in the garlic and poblano and cook for 2 minutes. Season with salt, usually about 1/2 teaspoon. Scrape the rajas into a bowl and cover to keep warm.
In a large bowl, combine the ground beef, cooked chorizo, chipotles and 1 1/2 teaspoon salt. Mix until well combined. Divide the meat into 4 equal portions and form the patties.
Heat a gas grill to medium-high, or light a charcoal fire and let it burn until the charcoal is covered with white ash (and about medium hot); bank the coals to one side.
Place the hamburger patties on the grill and cook for a total of 4 to 5 minutes for medium rare. Lay one piece of cheese on top of each burger, top with the warm rajas and then another piece of cheese. Close the lid and continue cooking until the cheese has melted about 1 minute. Remove from the grill and place on a toasted bun. Serve immediately.