Restaurant-style fajitas, one sheet pan, 20 minutes in the oven. The dinner that makes itself.
I used to spend $24 on fajitas at restaurants. Then I figured out how to make them better at home in less time than it takes to drive there. These keto sheet pan fajitas are the laziest impressive dinner I make — one pan, 20 minutes, and the oven does all the work.
The flavor comes from a homemade fajita seasoning that’s miles better than the packets at the store. No fillers, no caked-on cornstarch, just real spices in real amounts. You’ll make this seasoning once and use it on chicken, shrimp, eggs, vegetables, anything you want to wake up.
At 3.2g net carbs and 14.7g protein per serving, this is keto, low-carb, gluten-free, and the kind of dinner that proves “easy” and “delicious” aren’t mutually exclusive.
Why You’ll Love This Recipe
- One sheet pan, one bowl, twenty minutes. Minimal mess, minimal time.
- 3.2g net carbs and 14.7g protein per serving. Real macros, real food.
- Homemade fajita seasoning included. Make it once, use it everywhere.
- Endlessly customizable. Swap proteins, swap veggies, change the heat — same easy method.
- Naturally gluten-free and keto-friendly. Friendly for low-carb, paleo, gluten-free, and Whole30 eaters.
Ingredients You’ll Need
For the fajitas (serves 4):
- 1 lb beef, cut into strips — skirt, flank, or sirloin all work beautifully.
- 20g yellow onion, cut into strips — adds sweetness as it caramelizes.
- 166g bell pepper, cut into strips — mix red, yellow, and green for color and flavor variety.
- 1 tbsp high-heat oil — avocado or refined coconut both work great.
- 2 tbsp homemade fajita seasoning — recipe below.
- Salt and pepper to taste
For the homemade fajita seasoning:
- 3 tbsp chili powder
- 1 tbsp chipotle chili powder
- 2 tbsp smoked paprika
- 2 tsp onion powder
- 1 tsp garlic powder
- 1 tsp cumin
- ½ tsp cayenne pepper
- 2 tsp salt
How to Make Keto Sheet Pan Fajitas
Step 1: Make the Fajita Seasoning
Combine all the seasoning ingredients in a small bowl or jar and mix well. This makes more than you need for this recipe — store the rest in an airtight container and you’ll have homemade fajita seasoning ready whenever you want it.
Step 2: Preheat the Oven
Preheat your oven to 400°F.
Step 3: Season the Sheet Pan
On a large sheet pan, add the sliced beef, bell pepper strips, and onion. Drizzle with the high-heat oil, then sprinkle on 2 tablespoons of the fajita seasoning along with salt and pepper to taste.
Step 4: Toss to Coat
Mix everything together right on the sheet pan until the beef and vegetables are evenly coated with oil and seasoning. Spread it out into a single even layer.
Step 5: Bake
Bake for 20 minutes, until the beef is cooked through and the vegetables are tender with slightly charred edges.
Step 6: Serve
Pile high and serve with your favorite low-carb toppings — sour cream, guacamole, salsa, shredded cheese, fresh cilantro, lime wedges. Wrap them in low carb tortillas, cabbage leaves, or eat straight from the pan.
Expert Tips for the Best Results
- Cut the beef and vegetables to similar sizes. Even strips means even cooking. Big chunks of pepper next to thin slices of beef means one is overcooked while the other is underdone.
- Don’t overcrowd the pan. Use a large sheet pan and spread everything in a single layer. Crowded pans steam — they don’t roast. Use two pans if you need to.
- Make the seasoning in bulk. This recipe makes more than 2 tablespoons, so jar the extra and use it on chicken, shrimp, eggs, roasted veggies — anywhere you want bold smoky-spicy flavor.
- Add the bell peppers and onions later if you like them crunchier. Add the beef first and roast for 10 minutes, then add the veggies and roast another 10. Or do it all at once for fully softened vegetables.
- High heat is your friend. 400°F gets you the slight char on the edges that makes fajitas taste like fajitas.
Variations & Substitutions
- Swap the protein — chicken, shrimp, pork, or steak all work beautifully with the same seasoning and method. Cooking times may vary slightly (shrimp cooks faster, chicken about the same as beef).
- Add more vegetables — sliced mushrooms, zucchini strips, or jalapeños all roast well alongside the peppers and onions.
- Make it spicier — add more cayenne to the seasoning, or toss in fresh jalapeño slices before roasting.
- Make it milder — reduce or skip the cayenne and chipotle chili powder for a kid-friendly version.
- Different cuts of beef — skirt steak is most authentic for fajitas, but flank, sirloin, or even chuck strips all work.
Storage & Meal Prep
Use your nose on this one — keep it until it either smells off or you don’t want to look at it anymore.
Refrigerator: Store leftovers covered in the fridge. The flavor actually deepens overnight as the seasoning settles into the beef.
Meal prep: This recipe is meal-prep gold. Make a double batch on Sunday, portion into containers, and you’ve got grab-and-go lunches for the week. Reheat in a pan over medium heat (faster) or in the oven at 350°F for 10 minutes (better texture).
The fajita seasoning: Stores beautifully in an airtight container for months. Make a big batch and use it across the year.
Nutrition Information (Per Serving)
Makes 4 servings. Macros do not include sour cream or other toppings.
- Calories: 208
- Fat: 13.3g
- Carbs: 4.1g
- Fiber: 0.9g
- Net carbs: 3.2g
- Protein: 14.7g
Frequently Asked Questions
What’s the best cut of beef for fajitas? Skirt steak is the traditional choice — it has great flavor and stays tender when cut against the grain. Flank steak is a close second. Sirloin works in a pinch and is more budget-friendly. Whatever cut you use, slice it into strips against the grain for the most tender bite.
Can I make this in a skillet instead of the oven? Absolutely. Heat a large skillet over high heat, add the oil, then add the beef and vegetables. Stir-fry for about 8-10 minutes until everything is cooked and slightly charred. The oven method is more hands-off, but stovetop gets you faster.
What do I serve fajitas with on keto? Low carb tortillas (Hero, Mission Carb Balance), butter lettuce or cabbage leaves as wraps, cauliflower rice, or just on their own with sour cream, guacamole, salsa, and shredded cheese. They’re surprisingly satisfying without a wrap at all.
Can I use store-bought fajita seasoning? You can, but most store-bought packets have fillers, anti-caking agents, sugar, and a bunch of stuff you don’t need. The homemade version takes 2 minutes to mix up, tastes better, and lasts months. Worth it.
How spicy is this recipe as written? Moderate. The cayenne and chipotle chili powder add a noticeable warmth, but it’s not overwhelming. Adjust up or down based on your heat tolerance.
Can I prep this in advance? Yes — you can slice the beef and vegetables and even toss them with the seasoning and oil up to 24 hours ahead. Store covered in the fridge, then spread on a sheet pan and bake when ready.
If you make these, tag @ketowilder on Instagram — I want to see your fajita night.
