Cut the sirloin steak into thin strips and place it in a large mixing bowl, along with the rest of the ingredients. Use your hands to toss everything together until everything is well-coated in oil and seasoning.

Transfer this mixture to a large zip lock bag or tupperware container. Seal and refrigerate overnight (at least 1 hour, up to 48 hours).

When you’re ready to cook the fajitas, heat a large skillet over medium-high heat and simply transfer the fajitas mixture to the skillet. Cook, stirring occasionally, until the beef and vegetables have reached desired done-ness, about 10 to 15 minutes total. Taste the fajitas for flavor and add sea salt and/or hot sauce to taste.

Serve fajitas as-is for a low-carb option, or with cauliflower rice, steamed rice, tortillas, guacamole, cheese, etc. You can use the fajitas to make fajita tacos, burritos, burrito bowls, taco salads, and more!