Slice the 1 ¼ lb pork tenderloin thinly sliced against the grain into thin strips, about ¼-inch thick, cutting against the grain. In a mixing bowl, combine the 1 ¼ lb pork tenderloin thinly sliced against the grain with 2 tbsp soy sauce, 1 tbsp cornstarch, 1 tsp sesame oil, and 1 tbsp Shaoxing wine (if using). Toss well to coat evenly. Let marinate at room temperature for at least 10 minutes while you prep everything else.

In a mixing bowl, whisk together the 2 tbsp soy sauce, 1 tbsp oyster sauce, 1 tbsp hoisin sauce, 1 tbsp brown sugar, 1 tbsp cornstarch, ½ cup low-sodium chicken broth, and 1 tsp sesame oil until smooth and the 1 tbsp cornstarch is fully dissolved. Set aside near the stove.

Prep all vegetables before turning on the heat: slice the 1 red bell pepper cored and thinly sliced, 2 stalks celery sliced on the diagonal, 1 cup snap peas strings removed, and 3 stalks green onions white and green parts separated. Mince the 6 cloves garlic and grate the 1 ½ tbsp fresh ginger peeled and finely grated or minced. Keep everything in separate small piles — stir frying moves fast and you won't have time to chop once you start.

Heat a wok or skillet over the highest heat your stovetop allows. Let it get very hot — about 1–2 minutes. Add 1 tablespoon of neutral oil such as vegetable or avocado oil and swirl to coat. When the 2 tbsp neutral oil such as vegetable or avocado oil just begins to smoke, add the 1 ¼ lb pork tenderloin thinly sliced against the grain in a single layer. Let it sear undisturbed for 60 seconds, then stir fry for another 1–2 minutes until just cooked through and lightly browned. Transfer the 1 ¼ lb pork tenderloin thinly sliced against the grain to a clean plate and set aside.

Return the wok to high heat and add the remaining 1 tablespoon of neutral oil such as vegetable or avocado oil. Add the white parts of the green onions white and green parts separated, 6 cloves garlic, and 1 ½ tbsp fresh ginger peeled and finely grated or minced. Stir fry for 30–45 seconds until fragrant — do not let the 6 cloves garlic burn.

Add the 1 red bell pepper cored and thinly sliced and 2 stalks celery sliced on the diagonal. Stir fry for 2 minutes, tossing constantly, until they begin to soften slightly but still have a good crunch.

Add the 1 cup snap peas strings removed and stir fry for 1 more minute.

Return the cooked 1 ¼ lb pork tenderloin thinly sliced against the grain to the wok. Give the sauce a quick stir (the 1 tbsp cornstarch settles), then pour it over everything. Toss constantly for 1–2 minutes until the sauce thickens and coats every piece of pork tenderloin thinly sliced against the grain and vegetable in a glossy glaze.

Remove from heat. Taste and adjust seasoning — add a tiny splash of soy sauce if it needs salt, or a pinch of brown sugar to balance. Scatter the green tops of the green onions white and green parts separated over the top. Garnish with toasted 1 tsp sesame seeds if desired. Serve immediately over steamed white rice or noodles.