Note: "chipotles adobabo" are pickled smoked peppers in tomato sauce These indoor fajitas are for the dead of winter, when the grill is buried under a snowdrift, or for any time, really, when you just don't want to cook outdoors. This marinade is slightly different from the one we use for our grilled fajitas (above), it boosts the flavor with chipotles and liquid smoke flavoring to make up for the lack of an open flame.
Cook these in one or two heavy cast-iron skillets or on a large ridged cast-iron grill pan that will fit across two burners. (Those cute little fajita skillets that come with a wood or wicker holder are useless for cooking on, but two or three can be preheated and used as serving pieces.) Be sure to turn off the smoke alarm before setting out to make this recipe.
In a food processor, puree salsa, red onions, cilantro, 2 tablespoons of the olive oil, the chipotles, tequila, lime juice, and liquid smoke. Stir in the beer.
In a shallow non-reactive dish, pour the marinade over the skirt steak and let it stand at room temperature, covered, turning it once or twice, for 2 hours. Heat one or two heavy cast-iron skillets or a cast-iron stove-top grill pan over medium-high heat. When they are very hot, lightly coat the skillets with nonstick cooking spray. Letting the excess marinade drip off, and working in batches if necessary, place the meat in the skillets.
Cook, turning once or twice, until browned on the outside and medium-rare inside, 4 to S minutes per side.
Transfer the meat to a cutting board and let it rest for 10 minutes.
Meanwhile, in a large heavy skillet over medium heat, warm the remaining 2 tablespoons of olive oil. Stir in the onions and sweet red peppers, season with salt, and cook, covered, stirring once or twice, for 8 minutes. Cut the meat, across the grain and at a slight angle, into thin slices. Add the meat and any juices from the cutting board to the skillet with the onions and peppers.
Raise the heat to high and cook uncovered, tossing and stirring, until the meat is heated through and the onions and peppers are lightly browned, about 5 minutes.
Transfer to heated fajita pans or a large heated platter and serve immediately, accompanied by warmed tortillas, pico de gallo, and guacamole.