Fajita Flank Steak with Peppers & Onion #WeekdaySupper

This post is sponsored by Workman Publishing Company in conjunction with a social media campaign through Sunday Supper LLC. All opinions are my own. This post contains affiliate links.

Fajita Flank Steak from Sheet Pan Suppers #WeekdaySupper via I'm Not the Nanny

Busy moms and dads rejoice! Weekday suppers will no longer be a struggle thanks to the new cookbook Sheet Pan Suppers by Molly Gilbert.

Some home cooks swear by their slow cookers, but my oven is my secret weapon. Many weeknight dinners are made by raiding my pantry and tossing them on a sheet pan. I slide everything in my hot oven for own version of “set it and forget it.” Somehow it always comes out amazing. My husband jokingly calls my process ‘Iron Chef Kitchen.” I call it creativity under pressure.

Sheet Pan Suppers Cookbook Review via I'm Not the Nanny #WeekdaySupper

For those who don’t like improv in the kitchen, grab a copy of the new cookbook by Molly Gilbert, Sheet Pan Suppers: 120 Recipes for Simple, Surprising, Hands-Off Meals Straight from the Oven. To Gilbert, sheet pan cooking “means roasting, baking, and broiling.” True to her promise, every recipe is cooked in the trusty oven, including breakfast and desserts. The recipes are riffs of familiar dishes: buffalo chicken drumsticks & charred romaine; baked crab and corn cakes; and fajita flank steak with peppers and onions–which is what I made for our family.

My husband and I have consumed many sizzling platters of steak and pepper fajitas in tex-mex restaurants all over the country, but we’ve never made it at home. My kids helped make the marinade the night before. Roasting the vegetables and broiling the flank steak took only 20 minutes. While the steak rested, we made fresh guacamole and set the table.

Flank Fajitas Close Up via I'm Not the Nanny #WeekdaySupper

The kids declared the dish a winner and requested leftover flank for the next day’s lunch. We’re definitely making this dish again!  Gilbert’s recipe was easy to follow. I can’t wait to try more of her recipes.

Important note: Gilbert’s instructions are specifically for electric ovens. While the baking and roasting instructions won’t differ very much for gas ovens (where broilers are at the bottom, not the top), you’ll have to wing it for recipes that call for broiling.

Sheet Pan Suppers Cookbook review via I'm Not the Nanny #WeekdaySupper

Ready to try these super easy and flavorful broiled fajitas? Enter using the Rafflecopter widget below to win a copy Sheet Pan Suppers (US addresses only).

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Fajita Flank Steak with Peppers & Onion

Fajita Flank Steak with Peppers & Onion

Yield: Serves 4-6
Prep Time: 2 hours
Cook Time: 10 minutes
Total Time: 2 hours 10 minutes

Recipe copyright © Molly Gilbert 2014. Used with permission from Workman Publishing Company.


  • 2½ pounds flank steak
  • 4 cloves garlic, minced
  • ¼ cup plus 2 tablespoons extra virgin olive oil
  • 3 tablespoons Worcestershire sauce
  • ¼ cup freshly squeezed lime juice (from 2 to 4 limes)
  • 1 tablespoon ground cumin
  • 1 tablespoon chili powder
  • 1 tablespoon sugar
  • ¼ teaspoon crushed red pepper flakes
  • 1 teaspoon kosher salt
  • Olive oil cooking spray
  • 4 bell peppers (any color), stemmed, seeded, and thinly sliced
  • 1 yellow onion, thinly sliced
  • 8 to 12 small (6-inch) flour or corn tortillas, for serving
  • ¼ cup chopped fresh cilantro leaves
  • Salsa, sour cream, sliced avocado, and Cotija cheese, for serving


Place the flank steak in a large zip-top bag or a shallow glass baking dish. Whisk together the garlic, olive oil, Worcestershire sauce, lime juice, cumin, chili powder, sugar, red pepper flakes, and salt in a small bowl. Reserve ¼ cup of the marinade for the vegetables and pour the rest over the flank steak, turning it to coat. Close up the bag or cover the baking dish and marinate the steak in the refrigerator for at least 2 hours, and up to 12.

When you’re ready to cook, preheat the oven to 450°F with one rack about 4 inches from the broiler, another rack in the center position, and another in the bottom position. Line a sheet pan with aluminum foil, and mist it with the cooking spray.

Toss the peppers and onion with the reserved ¼ cup marinade in a large bowl and spread them evenly on the prepared pan. Roast on the center rack until softened and starting to brown, 10 to 15 minutes.

Remove the pan from the oven and turn the oven to broil. Wrap a stack of tortillas in aluminum foil and set it aside.

Push the peppers and onion to the perimeter of the pan. Remove the flank steak from the marinade, allowing any excess liquid to drip off the meat, and place it in the center of the pan, surrounded by the vegetables.

Place the pan on the top rack and broil the steak, flipping it once, until it begins to char on the outside and an instant-read thermometer inserted into the thickest part of the meat registers 125°F for rare or 135°F for medium-rare, 3 to 5 minutes per side.

While the steak cooks, place the foil-wrapped tortillas on the bottom rack to warm through. Once the steak is finished cooking, remove the pan from the oven and turn the oven off. Leave the tortillas in the oven to continue warming while the steak rests.

Allow the steak to rest, loosely covered with foil, for 10 minutes before slicing it thinly against the grain. Sprinkle with the cilantro.

Serve the steak warm with the peppers and onion and tortillas. Pass the salsa, sour cream, avocado, and cheese at the table.

 Take a look at what my fellow #WeekdaySupper friends are cooking from Sheet Pan Suppers:

Weekday Supper Logo Learn more about Molly Gilbert on her blog Dunk & Crumble and check out her interview on Sunday Supper. Follow our Sheet Pan Suppers Pinterest board for more tasty inspiration.



  1. Cindy Kerschner May 6, 2015
  2. Magnolia Days May 6, 2015
  3. Jennifer Essad May 6, 2015
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  20. Jennifer Essad May 13, 2015
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