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Best sheet pan fajitas with steak and peppers on a sheet pan with lime slices and guacamole off to the side

Best Sheet Pan Fajitas with Steak (Whole30, Low Carb)

A quick and easy sheet pan fajitas recipe with super tender steak and a quick guacamole. With flank steak, peppers, and onions, this healthy Mexican recipe is a one-pan dinner. Whole30, paleo, low carb.
Course Main Course
Cuisine Mexican
Keyword meat and veggies, one-pan meal, sheet pan meal
Prep Time 20 minutes
Cook Time 15 minutes
Total Time 35 minutes
Servings 4 servings
Calories 567kcal


  • Broiler
  • Baking sheet
  • 2 small bowls
  • Large bowl
  • Tongs


For the Fajitas

  • ¼ cup avocado oil
  • 2-3 cloves garlic minced or pressed
  • 2 teaspoons chili powder
  • 1 tablespoon lime juice juice from half of one lime
  • 1 teaspoon oregano
  • 1 teaspoon ground cumin
  • 2 teaspoons salt
  • 3 large bell peppers preferably 1 red, 1 orange, 1 yellow; seeds removed, peppers sliced into ½"-wide strips
  • 1 large red onion halved and sliced into ¼"-wide pieces
  • 1 pound thinly-sliced flank steak or “fajita” steak

For the Guacamole

  • 3 large avocados peeled, pit removed
  • ¼ cup pico de gallo or fresh salsa store-bought or make your own
  • 1 tablespoon lime juice juice from half of one lime
  • 1 teaspoon salt

Suggested for Serving (All Optional)

  • salsa
  • lime wedges
  • fresh cilantro chopped
  • red onion chopped
  • radishes sliced
  • lettuce cups
  • tortillas if not on Whole30


  • Place oven racks so that oven is evenly divided into thirds. Place empty baking sheet on top oven rack and preheat broiler on High.

For the Fajita Veggies

  • In small bowl, mix together avocado oil, garlic, chili powder, lime juice, oregano, cumin, and salt.
  • Place sliced peppers and onions in large bowl. Pour half of avocado oil mixture over veggies and toss well to coat.
  • Carefully and quickly, remove baking sheet from oven and transfer marinated peppers and onion to baking sheet. Return baking sheet to oven and cook on top rack under broiler for 7 minutes, or until veggies begin to soften and brown.

For the Guacamole

  • While peppers and onions are in oven, make guacamole by adding all guacamole ingredients to small bowl. Mash to desired consistency and taste, adding more salt as desired. Set aside or chill until ready to serve.

For the Fajita Steak

  • Place sliced steak in large bowl that was used for peppers and onions. Top with remaining avocado oil marinade and toss well to coat.
  • After peppers and onions have cooked 7 minutes (or until softened and browned), carefully and quickly remove baking sheet from oven. Use tongs to rearrange pan, creating space between peppers and onions. Place marinated steak in spaces in one flat layer, being careful not to overlap or overcrowd.
  • Return baking sheet to oven. Cook 4 minutes, or until steak is uniformly browned on top. Steak will likely show medium-rare temperature on underside, not on top, so carefully use tongs to flip steak and check doneness. Add additional time as needed to reach desired doneness.

To Serve

  • Carefully remove baking sheet from oven. Garnish with guacamole and toppings as desired. Serve fajita vegetables and steak as-is, in burrito bowls with cauliflower rice, or with lettuce cups or tortillas (if not on Whole30).


  • For even more flavor to your steak, marinate it in half of the avocado oil mixture in the fridge for up to 12 hours before cooking. Just take it out of the fridge about 30 minutes before you cook it.
  • Make sure to prep all of your ingredients before starting. This recipe moves pretty quickly once you get going, so there's not time to stop and chop things halfway through!


Serving: 1serving | Calories: 567kcal | Carbohydrates: 25g | Protein: 29g | Fat: 42g | Saturated Fat: 7g | Polyunsaturated Fat: 5g | Monounsaturated Fat: 27g | Trans Fat: 1g | Cholesterol: 68mg | Sodium: 1921mg | Potassium: 1424mg | Fiber: 13g | Sugar: 7g | Vitamin A: 761IU | Vitamin C: 120mg | Calcium: 78mg | Iron: 4mg | Net Carbs: 12g