Keto Beef Pepper Steak

Keto Beef Pepper Steak is the ultimate weeknight dinner that doesn’t sacrifice flavor for your low-carb lifestyle. This colorful, savory stir-fry combines tender strips of marinated beef with crisp bell peppers in a rich, umami-packed sauce—all without the sugar and carbs of traditional pepper steak.

I discovered this recipe when I was craving my favorite Chinese takeout but needed to stick to my keto goals, and now it’s my go-to for satisfying that stir-fry craving. Ready in just 30 minutes with simple ingredients, this dish proves that eating keto can be delicious, vibrant, and incredibly easy.

Why You’ll Love This Recipe

• Seriously low-carb: Under 8g net carbs per serving, perfect for ketogenic diets
• Quick and easy: From prep to plate in 30 minutes—faster than takeout delivery
• Budget-friendly: Uses affordable cuts of beef and everyday vegetables
• Meal prep champion: Makes excellent leftovers for lunch throughout the week
• Restaurant-quality flavor: Better than takeout with complete control over ingredients
• Naturally gluten-free: When using coconut aminos instead of soy sauce
• Colorful and appealing: Those vibrant peppers make this dish Instagram-worthy

Equipment Needed

• Large skillet or wok (12-inch works best)
• Sharp knife and cutting board
• 2 medium mixing bowls
• Small bowl for sauce
• Measuring cups and spoons
• Tongs or wooden spoon for stirring
• Whisk (for sauce)

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Ingredients You’ll Need

Beef & Marinade

• 1 lb (450 g) flank steak or sirloin, thinly sliced against the grain
• 2 tablespoons soy sauce or coconut aminos (for strict keto)
• 1 teaspoon sesame oil
• 1 teaspoon minced garlic
• ½ teaspoon ground black pepper

Stir-Fry

• 2 tablespoons olive oil or avocado oil (divided)
• 1 medium green bell pepper, thinly sliced
• 1 medium red bell pepper, thinly sliced
• 1 medium yellow or orange bell pepper, thinly sliced
• 1 small onion, thinly sliced
• 2–3 cloves garlic, minced
• 1 inch fresh ginger, minced (optional but highly recommended)

Sauce (Keto-Friendly)

• ¼ cup beef broth or water
• 2 tablespoons soy sauce or coconut aminos
• 1 tablespoon rice vinegar or apple cider vinegar
• 1–2 teaspoons chili garlic sauce or hot sauce (optional for heat)
• ½–1 teaspoon low-carb sweetener (erythritol or monk fruit, optional)

Thickener (Keto-Friendly)

• 1 teaspoon xanthan gum

Garnish

• Sesame seeds
• Sliced green onions

Ingredient Notes

Beef Selection: Flank steak is my top choice for tenderness and flavor, but sirloin works beautifully too. For budget-friendly options, try skirt steak or even top round thinly sliced. The key is slicing against the grain—this shortens the muscle fibers and ensures tender bites.

Soy Sauce vs. Coconut Aminos: Regular soy sauce works fine for keto (it’s naturally low-carb), but coconut aminos are perfect if you need gluten-free or want a slightly sweeter, less salty flavor. Tamari is another excellent gluten-free alternative.

Bell Pepper Rainbow: Using three different colored peppers isn’t just pretty—each color offers slightly different flavors and phytonutrients. Red peppers are sweetest, green are most crisp, and yellow/orange fall somewhere in between. Feel free to use whatever colors you have on hand.

Xanthan Gum Magic: This keto-friendly thickener is your secret weapon for creating silky sauces without cornstarch. A little goes a long way—start with ½ teaspoon if you’re nervous. Find it in the baking aisle or near gluten-free products.

Fresh Ginger: Don’t skip this if you have it! Fresh ginger adds an authentic stir-fry flavor that ground ginger can’t replicate. Store leftover ginger in the freezer and grate it frozen—much easier than peeling and mincing.

Oil Choice: Avocado oil has a higher smoke point than olive oil, making it ideal for high-heat cooking. However, light olive oil works perfectly fine for this recipe.

Step-by-Step Instructions

Step 1: Marinate the Beef

In a medium bowl, combine the sliced beef with 2 tablespoons soy sauce or coconut aminos, 1 teaspoon sesame oil, 1 teaspoon minced garlic, and ½ teaspoon black pepper. Mix well until all beef strips are evenly coated. Let marinate for 10–20 minutes at room temperature while you prep your vegetables. This brief marinating time infuses the beef with flavor and helps tenderize it.

Step 2: Prep the Sauce

In a small bowl, whisk together ¼ cup beef broth, 2 tablespoons soy sauce or coconut aminos, 1 tablespoon vinegar, chili garlic sauce (if using), and sweetener (if using). Having your sauce ready before you start cooking ensures smooth, stress-free stir-frying. Set aside.

Step 3: Stir-Fry the Beef

Heat 1 tablespoon of oil in a large skillet or wok over medium-high heat until shimmering. Add the marinated beef in a single layer—don’t overcrowd the pan or the beef will steam instead of sear. Cook for 2–3 minutes per side until nicely browned but not fully cooked through (it will finish cooking later). Remove the beef from the pan and set aside on a plate.

Step 4: Cook the Veggies

Add the remaining 1 tablespoon of oil to the same pan (don’t wipe it out—those browned bits add flavor). Add the sliced bell peppers and onion. Stir-fry for 3–5 minutes, tossing frequently, until the vegetables are crisp-tender with some charred edges. Add the minced garlic and ginger (if using) and stir for 30–60 seconds until fragrant. Don’t let the garlic burn.

Step 5: Combine & Sauce

Return the seared beef to the pan with the vegetables. Pour in the prepared sauce and toss everything together to combine. Cook for 2–3 more minutes, stirring occasionally, so the flavors meld and the beef finishes cooking to your desired doneness.

Step 6: Thicken (Keto Style)

While stirring constantly, sprinkle the xanthan gum evenly over the mixture. Continue stirring for about 1 minute until the sauce thickens to a glossy, coating consistency. Important: Xanthan gum works extremely fast, so don’t walk away! If you add too much, the sauce can become gummy, so start conservatively.

Step 7: Finish & Serve

Remove the pan from heat immediately once the sauce reaches your desired thickness. Transfer to a serving platter or individual bowls. Garnish generously with sesame seeds and sliced green onions for that restaurant-quality presentation. Serve hot and enjoy your keto-friendly pepper steak!

Pro Tips & Cooking Hacks

• Freeze beef for 15 minutes before slicing—it firms up and makes getting those thin, even slices much easier
• Use kitchen shears to slice the beef right in the bowl if you find cutting easier that way
• Don’t overcrowd your pan—if your skillet isn’t large enough, cook the beef in two batches for better browning
• Save the marinade and add it to the sauce for extra flavor (it’s only been sitting for 20 minutes, perfectly safe)
• Prep everything before you start cooking—stir-frying moves fast, and you won’t have time to chop mid-cook
• Add a splash of water if your sauce gets too thick; you can always thicken more but can’t un-thicken easily
• Toast your sesame seeds in a dry pan for 2 minutes before garnishing for deeper, nuttier flavor
• Keep vegetables crisp—don’t overcook them; they should still have a slight crunch for the best texture
• Double the sauce if you like your stir-fry extra saucy (perfect for serving over cauliflower rice)
• Use a wok if you have one—the high sides and rounded bottom make tossing ingredients much easier

Tips & Variations

Storage: Store leftovers in an airtight container in the refrigerator for up to 4 days. The flavors actually deepen overnight, making this an excellent meal prep option. Reheat gently in a skillet over medium heat or microwave in 30-second intervals, stirring between each.

Freezer-Friendly: This dish freezes well for up to 3 months. Let it cool completely, then portion into freezer-safe containers. Thaw overnight in the fridge and reheat on the stovetop. The peppers may be slightly softer after freezing, but the flavor remains fantastic.

Make-Ahead: You can slice the beef and vegetables up to 24 hours in advance. Store separately in the fridge. Marinate the beef right before cooking for best results, or marinate it overnight for even more tender meat.

Spice It Up: Add red pepper flakes, sriracha, or extra chili garlic sauce for more heat. A teaspoon of sambal oelek gives it an authentic Asian kick.

Veggie Variations: Add snap peas, broccoli florets, mushrooms, or baby bok choy for more variety. Zucchini noodles mixed in at the end add volume without many carbs.

Protein Swaps: Use chicken breast, pork tenderloin, or shrimp instead of beef. Adjust cooking times accordingly (shrimp cooks in just 2–3 minutes total).

Whole30/Paleo: Use coconut aminos, omit the sweetener, and ensure your chili sauce has no added sugar.

Dairy-Free: This recipe is naturally dairy-free as written—perfect for those with lactose sensitivities.

Serving Suggestions

Serve this Keto Beef Pepper Steak over cauliflower rice for a complete low-carb meal that mimics traditional pepper steak over white rice. Shirataki noodles (miracle noodles) are another excellent zero-carb option that soaks up the delicious sauce. For a lighter approach, enjoy it on its own as a protein-and-veggie bowl, or serve alongside steamed broccoli, sesame green beans, or an Asian cucumber salad.

This dish pairs beautifully with other keto-friendly sides like garlic butter mushrooms, roasted Brussels sprouts with bacon, or a simple mixed greens salad with ginger dressing. For a complete Asian-inspired dinner, serve it alongside keto egg drop soup or miso soup with tofu. Don’t forget the cauliflower fried rice—it’s a match made in low-carb heaven!

Common Mistakes

• Cutting beef with the grain instead of against it—this results in tough, chewy meat that’s hard to enjoy
• Overcooking the beef in the first sear—remember, it will cook again with the vegetables and sauce
• Using too much xanthan gum—it thickens rapidly and can turn your sauce into gel if you’re not careful
• Not heating the pan enough—a properly hot pan creates that delicious sear and prevents sticking
• Adding garlic too early—garlic burns easily and turns bitter; always add it near the end of vegetable cooking
• Skipping the marinating step—even 10 minutes makes a difference in flavor and tenderness
• Using ground ginger instead of fresh—the flavor is completely different and won’t give authentic results
• Overcrowding the pan—this steams the beef instead of searing it, resulting in gray, boiled-looking meat
• Not preparing mise en place—stir-frying happens fast; have everything chopped and ready before you start

What to Serve With Keto Beef Pepper Steak

This vibrant stir-fry is substantial enough to serve as a complete one-bowl meal, but it shines when paired with keto-friendly sides that complement its savory, umami-rich flavors. Cauliflower rice is the classic pairing—it soaks up all that delicious sauce and keeps your carb count low while adding satisfying volume to your plate. For a fun twist, try shirataki noodles or zucchini noodles for a lo mein-inspired experience that’s entirely keto-approved.

Round out your Asian-inspired dinner with sides like roasted sesame broccoli, spicy garlic bok choy, or a crisp cucumber salad with rice vinegar dressing. If you want to make it a feast, add keto egg drop soup as a starter or some crispy baked tofu for extra protein. The key is keeping sides simple so the star of the show—that beautifully seared, colorful pepper steak—gets the attention it deserves!

Frequently Asked Questions

Can I use a different cut of beef?

Absolutely! While flank steak and sirloin are ideal for their tenderness and flavor, you can use skirt steak, top round, or even ribeye if you’re feeling fancy. The most important thing is to slice whatever cut you choose thinly and against the grain. Tougher cuts benefit from longer marinating (up to 2 hours) or even a quick tenderizing with a meat mallet before slicing.

Is this recipe really keto-friendly?

Yes! This Keto Beef Pepper Steak contains approximately 7–8g net carbs per serving, making it perfectly suitable for ketogenic diets. The recipe uses no sugar or cornstarch, relies on xanthan gum for thickening, and features low-carb vegetables. Using coconut aminos instead of soy sauce and skipping the optional sweetener reduces carbs even further.

Can I make this without xanthan gum?

You can, but your sauce will be thinner and more like a glaze than a thick, coating sauce. If you don’t have xanthan gum, you can reduce the sauce by simmering it longer (though this concentrates saltiness too), or simply enjoy it as a lighter sauce. Guar gum works as a 1:1 substitute for xanthan gum if you have that instead.

How do I keep my bell peppers from getting mushy?

The key is high heat and quick cooking! Make sure your pan is very hot before adding the peppers, and don’t stir them constantly—let them sit for 30–60 seconds at a time to develop some char. Cook them just 3–5 minutes total; they should still have a crisp-tender bite, not be soft and floppy. Removing them from heat while they still have texture ensures they won’t overcook from residual heat.

Can I make this ahead for meal prep?

Yes! This dish is excellent for meal prep and actually tastes even better the next day as the flavors meld. Prepare the full recipe, let it cool completely, then divide into individual portions in meal prep containers. Store in the refrigerator for up to 4 days. Reheat gently on the stovetop or in the microwave. If you’re preparing for the week, consider slightly undercooking the vegetables so they maintain better texture after reheating.

💬 Tried this Keto Beef Pepper Steak recipe? Leave a comment and rating below! I’d love to hear how it turned out and what variations you tried.