I've tried many marinated fajita recipes over the years, but none have made an impression. This recipe is a keeper, though, and I've made it many times. I usually don't even marinade the chicken very long and it is super tasty.
UPDATE 2/23/16: Finally made a vegetarian version and it was delicious. I added the marinade (didn't measure - probably used half the amount of marinade) as I cooked the peppers and onions. After they were cooked, I added one can of drained black beans.
from Smitten Kitchen
1 1/2 pounds boneless, skinless chicken thighs
2 tablespoons lime juice (half a juicy lime)
1 1/2 teaspoons kosher salt
1 1/2 teaspoons dried oregano
2 teaspoons ground cumin
1 teaspoon chili powder
1/2 teaspoon smoked paprika
1 garlic clove, minced or pressed
Few dashes hot sauce, optional
8 (6-inch) flour or corn tortillas
2 large bell peppers, cut into thin strips (mix of any colors)
1 large yellow or sweet onion, halved and sliced thin
Accompaniments: black beans, salsa, avocado, cheese, etc.
In a bowl or freezer bag, add lime juice, spices and garlic and mix together. Slice chicken thighs into thin strips (1/4- to 1/2-inch wide) and add to marinade. Let marinate for 30 minutes or up to 2 days in the fridge.
Heat oven to 250 and wrap tortillas in foil. Set on rack to warm. Prepare accompaniments of your choice.
Cook peppers, onions and chicken: Heat your largest skillet (12-inch cast iron) on the highest heat. When very hot, drizzle in some olive oil to lightly coat the bottom of the pan. When this is nearly smoking hot, add the peppers in a single layer. Wait. Try to get them a little charred underneath before you move them around. Once they’ve begun to brown, add the onions, plus some salt. Wait again for some color to develop before you move them. When peppers are nicely charred in spots and onions have softened and sweetened, scrape mixture onto a plate or bowl to clear the skillet. Heat skillet again on a very high heat with a thin slick of olive oil. Spread chicken strips in as much of a single layer as you can. Wait until they brown underneath to move them. Saute strips, regularly pausing so that they can get some color, until cooked through, about 4 to 5 minutes. Return peppers and onions to skillet. Heat again until everything is sizzling and bring to the table.
Serve with warmed corn tortillas and other accompaniments.