Preheat your oven to 400 degrees Fahrenheit. Lining a baking sheet with foil makes for easy cleanup later.
Prepare the flank steak by slicing it into half-inch strips. This allows for quick cooking and maximizes flavor absorption.
In a bowl, whisk together 2 tablespoons of the ¼ cup olive oil, 1 ½ tablespoons of 3 tablespoons fajita seasoning, and 1 tablespoon of lime juice to create a marinade.
Add the sliced 1 pound flank steak to a ziplock bag, pour in the marinade, and let it rest while you prepare the vegetables. This resting time enhances the flavors.
Slice 1 yellow onion, 1 red bell pepper, 1 green bell pepper, and 1 yellow bell pepper into half-inch slices. These should all be roughly the same size for even cooking.
In a large bowl, toss the sliced vegetables in the remaining olive oil, fajita seasoning, and salt and pepper to taste. This ensures each piece is coated.
Spread the seasoned vegetables on one side of the lined baking sheet, leaving room for the steak. Place the marinated steak strips next to the vegetables.
Place the baking sheet in the preheated oven and bake the fajita mix for 12 to 15 minutes. Toss halfway through to ensure even cooking.
While the fajita mix is baking, toast the small flour or corn tortillas in a pan for added flavor and warmth.
Slice the limes and chop the cilantro. These will be used as fresh toppings.
Once the steak is cooked through and the vegetables are tender, remove the pan from the oven. Allow it to cool for a few minutes before serving.
Serve your Sheet Pan Steak Fajitas with your favorite toppings, including avocado, if desired. Enjoy!
