In a medium bowl, combine the soy sauce, honey, cornstarch, and cold water to create a smooth teriyaki sauce. Whisk the mixture until the cornstarch is fully dissolved, then set it aside.
Heat 1 tablespoon of olive oil in a large skillet or wok over medium-high heat until shimmering.
Add the sliced sirloin steak to the hot skillet in a single layer. Season with salt and freshly ground black pepper. Stir-fry for 2-3 minutes, or until the steak is nicely browned and cooked to your preferred level of doneness. Once cooked, remove the steak from the skillet and set it aside on a plate.
In the same skillet, add the remaining tablespoon of olive oil. Once hot, toss in the minced garlic and grated ginger, stirring for about 30 seconds until fragrant. Immediately add the sliced bell pepper, broccoli florets, and snap peas. Stir-fry the vegetables for 4-5 minutes, or until they are tender yet still crisp.
Return the cooked steak to the skillet with the vegetables. Pour the prepared teriyaki sauce over the mixture and toss everything together, ensuring all ingredients are evenly coated. Cook for an additional 1-2 minutes until the sauce is heated through and slightly thickened.
Remove the skillet from heat and garnish the stir-fry with chopped green onions and a sprinkle of sesame seeds for added crunch.
Notes
Serve with steamed jasmine rice for a complete meal.