Nothing beats a sizzling wok on a weeknight when you need dinner on the table in under 30 minutes. This Spicy Beef Stir Fry combines thin-sliced beef, crisp bell peppers, and a bold, garlicky sauce with just the right amount of heat. It’s faster than takeout, easy to customize, and comes together in one pan — perfect for busy evenings when you still want something that tastes like it took effort.
Ingredients You’ll Need
For the beef and marinade:
- 1 lb flank steak or sirloin, thinly sliced against the grain
- 1 tablespoon soy sauce
- 1 tablespoon cornstarch
- 1 teaspoon sesame oil
For the stir fry:
- 2 tablespoons vegetable oil, divided
- 1 red bell pepper, sliced
- 1 green bell pepper, sliced
- 1 small onion, sliced
- 3 cloves garlic, minced
- 1 tablespoon fresh ginger, minced
- 1–2 red chilies or 1 teaspoon red pepper flakes (adjust to taste)
- 2 green onions, chopped (for garnish)
- 1 teaspoon sesame seeds (optional garnish)
For the sauce:
- 3 tablespoons soy sauce
- 1 tablespoon oyster sauce
- 1 tablespoon rice vinegar
- 1 tablespoon brown sugar
- 1 teaspoon sriracha or chili garlic sauce
- 1/4 cup beef broth or water
- 1 teaspoon cornstarch (to thicken)
How to Make (Step-by-Step)
1. Marinate the beef. In a bowl, toss the sliced beef with soy sauce, cornstarch, and sesame oil. Let it sit for at least 15 minutes at room temperature — this tenderizes the meat and helps the sauce cling later.
2. Mix the sauce. While the beef marinates, whisk together the soy sauce, oyster sauce, rice vinegar, brown sugar, sriracha, broth, and cornstarch in a small bowl. Set aside.
3. Sear the beef. Heat 1 tablespoon of oil in a wok or large skillet over high heat until shimmering. Add the beef in a single layer and let it sear undisturbed for about 1 minute before stirring. Cook for 2–3 minutes total, until browned but not fully cooked through. Remove and set aside.
4. Stir-fry the vegetables. Add the remaining oil to the pan. Toss in the bell peppers and onion, stir-frying for 2–3 minutes until just crisp-tender. Add the garlic, ginger, and chilies, and cook for another 30 seconds until fragrant.
5. Combine and finish. Return the beef to the pan. Pour in the sauce and stir everything together. Cook for 1–2 minutes, until the sauce thickens and coats the beef and vegetables evenly.
6. Garnish and serve. Remove from heat, top with green onions and sesame seeds, and serve hot over steamed rice or noodles.
Recipe Tips
- Slice against the grain. Cutting the beef against the muscle fibers, not with them, is the single biggest factor in tender stir-fried beef.
- Use high heat. A screaming-hot pan sears the beef quickly and prevents it from turning gray and steaming instead of browning.
- Don’t overcrowd the pan. Cook the beef in batches if needed — too much meat at once lowers the pan temperature and stews the meat rather than searing it.
- Prep everything first. Stir-frying moves fast, so have all ingredients sliced, minced, and measured before you turn on the heat.
- Control the heat level. Start with less chili and add more sriracha or flakes at the end if you want it spicier — it’s easier to add heat than take it away.
Storage & FAQ
FAQ
Can I use a different cut of beef?
Yes. Flank, sirloin, skirt steak, and even ribeye all work well. Just make sure to slice thinly against the grain for the best texture.
What can I substitute for oyster sauce?
Hoisin sauce or a mix of soy sauce and a touch of brown sugar can work in a pinch, though the flavor will be slightly sweeter and less savory.
Is this dish very spicy?
As written, it has a moderate kick. You can dial it up with extra chilies and sriracha, or dial it down by omitting the fresh chilies and using just a small pinch of red pepper flakes.
What should I serve with it?
Steamed jasmine rice, fried rice, or lo mein noodles all pair well. A side of steamed broccoli or bok choy rounds out the meal.
How to Store
Let the stir fry cool to room temperature, then transfer it to an airtight container. It will keep in the refrigerator for up to 3–4 days. Reheat in a hot skillet or wok for a minute or two to revive the texture — microwaving works too, but the vegetables will be softer.
How to Freeze
This dish freezes reasonably well, though the bell peppers will soften upon thawing. Cool completely, then freeze in a freezer-safe container or bag for up to 2 months. Thaw overnight in the refrigerator before reheating in a hot pan. For best texture, consider freezing just the beef and sauce, and adding freshly cooked vegetables when you reheat.
Nutritional Info
Per serving (based on 4 servings):
| Nutrient | Amount |
|---|---|
| Calories | ~320 kcal |
| Protein | 28g |
| Carbohydrates | 14g |
| Fat | 17g |
| Saturated Fat | 4g |
| Fiber | 2g |
| Sugar | 7g |
| Sodium | 890mg |
Values are estimates and will vary based on specific ingredients and portion sizes used.