In a large, deep skillet or a wok, heat 1 tablespoon of avocado oil over medium-high heat. Add the beef and stir-fry for 2 minutes, just until no longer raw. Try not to overcook the beef - sirloin can become tough pretty easily. Using a slotted spoon, remove the meat to a plate.
2 tablespoons avocado oil, 1.5 pound top sirloin steak
To the same skillet, add the remaining oil, then add the onions and bell peppers and stir-fry until just tender, about 4 minutes.
1 onion, 2 bell peppers
Add the snow peas, garlic, and ginger. Cook, stirring, for 1 minute. If the pan gets too hot, lower the heat to medium. Try not to overcook the vegetables. Stir-fried veggies should be tender-crisp.
Mix the sauce again and add it to the skillet, then add the beef. Cook, stirring, until everything is well coated and the sauce slightly thickens, about 1 more minute. Keep this step brief to avoid overcooking the meat and vegetables.
Transfer the stir-fry to a serving platter. Drizzle it with sesame oil and sprinkle it with sesame seeds. Serve immediately.
1 tablespoon sesame oil, 1 teaspoon sesame seeds
Video
Notes
Seasonings, especially salt, are guidelines. Adjust to taste.
Instead of bell peppers and snow peas, you can use 2-3 cups of any chopped vegetable suitable for stir-frying, such as small broccoli florets, thinly sliced carrots, or button mushrooms.
If you enjoy spicy food, add a tablespoon of sriracha sauce to the soy sauce mixture.
Like all stir-fry recipes, prepping the vegetables takes the longest. Once you have everything prepped, cooking is a matter of minutes. So you should definitely prep everything in advance! Slice the vegetables and mix the sauce before you start cooking, because once you start, everything happens fast, and you won't have time for any prep work.
The best way to tenderize meat is with a marinade that contains vinegar. But if you use top sirloin strips and make sure you don't overcook them, the beef comes out quite tender. So, I don't bother with marinating it. However, if you wish, you can place the beef strips in a resealable bag, add a mixture of avocado oil and rice vinegar (2 tablespoons of each) plus a teaspoon of minced garlic, seal the bag well, place it on a plate, and refrigerate it overnight.
You can keep the leftovers in an airtight container in the fridge for 3-4 days. Reheat them gently, covered, in the microwave at 50% power. The cooled leftovers can also be frozen in a freezer-safe container or freezer bags for up to three months.