In a medium-sized bowl, toss the pork with 1/2 tablespoon of balsamic vinegar and a pinch of salt.
1 lb. pork tenderloin, trimmed of excess fat and silverskin removed, cut into 1/2" pieces, 2-1/2 tbsps balsamic vinegar, kosher salt
In another small bowl, combine the remaining 2 tablespoons of vinegar, soy sauce, cornstarch, ketchup, 3 tablespoons of sugar, 1/3 cup of water, and 1/2 teaspoon of kosher salt.
2 tsps low sodium soy sauce, 1 tbsp cornstarch, 3 tbsps ketchup, 3 tbsps granulated sugar, 1/3 cup water
Heat 2 tablespoons of oil in a large skillet over high heat. Add the pork and stir slowly until it turns mostly opaque, about 2 minutes. Remove the pork with a slotted spoon and transfer it to a plate. Discard the oil and wipe out the skillet
3 tbsps peanut oil
Heat the remaining 1 tablespoon of oil in the skillet, then stir-fry the garlic with a pinch of salt and sugar (only for 15 seconds, as it can burn quickly). Add the carrots and scallions, and stir-fry until crisp-tender, about 2 minutes. If the mixture seems dry, add a small splash of water. Add the pork, snow peas, and soy sauce mixture, stirring until the pork is cooked through and the sauce has thickened, about 3 minutes.
3 cloves garlic, minced, 2 carrots, thinly sliced, 3 scallions, cut into 1/2" pieces, 3 cups snow peas, cut in half