My Favorite Fajitas

Smoke the skirt steak according to the directions below.

To make the marinade: while the steak is cooling, toast the cumin seeds in a small skillet over medium-low heat, shaking the constantly so they don't burn or stick, just until they are fragrant, about 3 minutes. Let them cool, Squeeze the juice from the limes into 1-gallon heavy plastic resealable bag. Add the cumin seeds, garlic, salt, and the pepper flakes and swish the marinade around to dissolve the salt. Slip the cooled steaks into the marinade, press out most of the air from the bag, and seal the bag very tightly. Refrigerate the beef for at least 4 hours or up to 1 day, turning the bag several times.

To prepare the accompaniments, heat the vegetable oil in a large, deep, skillet over medium heat. Stir in the red onions and cook, stirring often, until they are wilted, about 5 minutes. Add the green peppers and cook until they are wilted enough t make room for the red peppers. Add the red peppers, season the vegetables lightly with salt and adjust the heat to low. Cook, stirring often, until tender, about 20 minutes. The vegetables can be prepared several hours in advance. Reheat them over low heat just before serving.

To prepare the fajitas indoors: Preheat the oven to 350 degrees F. Wrap the tortillas in aluminum foil. Reheat the vegetables if necessary. Drain the steak well and discard the marinade. Heat a lightly oiled large grill pan or heavy skillet over medium-high heat until smoking. Cook the steak, turning once, just until seared on both sides, about 5 minutes. At this point the steak will be about medium-rare. Turn off the heat and continue cook in the hot pan for a more well-done steak. Remove the steak from the skillet to a carving board and let it rest about 5 minutes. Pop the tortillas into the oven and let them warm while the steak is resting.

To prepare the fajitas on a charcoal or gas grill: Wrap the tortillas in aluminum foil. Reheat the vegetables if necessary, using a corner of the grill if there is room. Drain the steak well and discard the marinade. Cook the steak on the hottest part of the grill until both sides are well browned, about 6 minutes. The steak at this point will be about medium-rare, move the steak to a cooler part of the grill and continue to cook it for a more well-done steak. Remove the steak to a carving board and let it rest about 5 minutes. Set the tortilla on a moderately hot part of the grill and let them warm, turning once or twice, while the steak rests.

To serve: Cut the steak crosswise into thin slices and pile the slices on a serving plate. Serve the vegetables directly from the skillet or scoop them into a serving bowl. Pass the tortillas, salsa, sour cream , steak, and vegetables around the table and let everyone dress their own fajitas as they like.