Spicy Beef Pepper Stir Fry

There's a rhythm to stir-fry that I stumbled into late one Tuesday when I was scrambling to cook something substantial in under thirty minutes. The sizzle of beef hitting a screaming hot wok, the impossible speed of it all—I was hooked immediately. What started as pure desperation became my go-to when I want something that tastes like I've been cooking all day but actually takes less time than scrolling through my phone.

I made this for my sister's surprise weeknight dinner, and she couldn't believe how vibrant and alive the peppers stayed—still snappy despite the heat. She asked if I'd been practicing in secret, which made me laugh because the whole thing was genuinely improvised that first time.

Ingredients

• Flank steak or sirloin, 400g, thinly sliced: Slicing against the grain is the quiet trick that makes all the difference—it breaks up the muscle fibers so every bite feels tender instead of chewy.
• Soy sauce (for marinade), 1 tbsp: This does double duty as both tenderizer and seasoning.
• Cornstarch, 1 tbsp: Creates a silky coating that helps the beef brown beautifully and cling to the sauce.
• Sesame oil, 1 tsp: Use the toasted kind—it's worth seeking out and changes everything about the flavor.
• Black pepper, 1/2 tsp: Freshly ground pepper tastes sharp and alive compared to the pre-ground stuff.
• Red, yellow, and green bell peppers, 1 of each: The colors aren't just for show—they each bring slightly different sweetness levels.
• Red onion, 1 small, thinly sliced: Adds a gentle bite that softens as it cooks.
• Garlic and ginger, 2 cloves and 2 cm: These two are the flavor foundation—don't skip or rush this step.
• Soy sauce (for sauce), 2 tbsp: The second amount keeps the umami building.
• Oyster sauce, 1 tbsp: Adds depth and a subtle sweetness that rounds out the spice.
• Rice vinegar, 1 tbsp: Cuts through the richness and keeps everything bright.
• Chili garlic sauce, 1 tbsp: Start conservative here—you can always add more heat.
• Brown sugar, 1 tsp: A tiny bit of sweetness balances the spice and salty elements.
• Vegetable oil, 2 tbsp: Use an oil with a high smoke point like peanut or canola.
• Spring onions and sesame seeds, for garnish: The final touch brings freshness and nutty texture.

Instructions

Coat the beef with its flavor foundation:

Mix soy sauce, cornstarch, sesame oil, and pepper in a bowl with your beef strips. The cornstarch will look chalky at first—keep tossing until it looks sandy and the meat is evenly coated. This 10-minute rest lets the flavors start working into the meat.

Prepare your sauce in advance:

Whisk soy sauce, oyster sauce, rice vinegar, chili garlic sauce, and brown sugar in a small bowl. Having this ready means you won't scramble for measurements once the wok is screaming hot.

Sear the beef without moving it:

Heat 1 tablespoon oil over high heat until it shimmers and almost smokes. Add the beef in a single layer and let it sit undisturbed for 2–3 minutes—you want a golden crust forming, not gray meat. Only then stir it around for another minute until browned.

Build the aromatics:

Add the remaining oil and immediately toss in garlic, ginger, and onion. The kitchen will smell incredible within seconds—that's your signal they're releasing their magic.

Coax color and crunch from the peppers:

Add the bell peppers and let them cook for 2–3 minutes, stirring occasionally. You want them softer than raw but still with a slight snap when you bite them.

Bring everything together:

Return the beef to the wok and pour in your prepared sauce. Toss everything quickly so every piece gets coated. Watch it thicken slightly—that's your sign it's ready, usually 1–2 minutes.

Finish with fresh accents:

Remove from heat and scatter spring onions and sesame seeds on top. The warmth will soften the onions just enough while keeping them fresh.

Save

I learned the hard way that stir-fry is about restraint—adding too much at once drops the wok temperature and ruins the whole thing. Now I treat it like a conversation: each component gets its moment to cook before the next one joins in.

Adjusting the Heat Level

The chili garlic sauce is where your heat lives, and honestly, 1 tablespoon can feel gentle or fiery depending on the brand. Start with half and taste as you go—you can always stir in more, but you can't take it back. I've had guests who thought this was mild and others who needed extra rice to cool down, all from the same batch.

Why This Works as a Weeknight Dinner

The magic is the 15-minute prep window where you can get everything prepped while the beef marinates. By the time you're actually cooking, you're just executing simple movements in a hot wok, no scrambling for ingredients. It's the kind of meal that builds your confidence in the kitchen without demanding precision.

Building Your Stir-Fry Pantry

Once you've made this once, you'll find yourself craving stir-fry regularly, and that's when it helps to keep a few staples stocked. Good soy sauce, sesame oil, rice vinegar, and chili garlic sauce are the four pillars—having these on hand means you can improvise with whatever vegetables or proteins you have.

• Toast your sesame seeds in a dry pan for 2–3 minutes to wake up their flavor before sprinkling them on.
• If your peppers are thick and chunky, they'll take longer—cut them thinner for this quick-cook method.
• Serve immediately over steamed rice so the heat carries the sauce flavors into every grain.

Save

This dish has become the thing I cook when I want to feel capable and have something delicious ready in under half an hour. It's proof that weeknight cooking doesn't have to mean compromise.

Recipe FAQs

→ How do I ensure the beef stays tender and juicy?

Marinate the beef with soy sauce, cornstarch, and sesame oil for at least 10 minutes before cooking. Cook it quickly over high heat to avoid drying out.

→ Can I adjust the spice level in this dish?

Yes, adjust the amount of chili garlic sauce to your preferred heat. Start with less and add more to taste.

→ What vegetables work best for stir frying here?

Bell peppers in red, yellow, and green provide color and crunch. Adding thinly sliced red onion, garlic, and ginger enhances aroma and flavor.

→ Is there a way to make this dish gluten-free?

Use gluten-free soy sauce and oyster sauce alternatives to avoid gluten contamination.

→ What can I use to garnish this stir fry?

Sliced spring onions and toasted sesame seeds add a fresh, nutty finish that complements the bold flavors.