In a mixing bowl, combine soy sauce, water, rice vinegar, light brown sugar, minced garlic, minced ginger, crushed red pepper, and cornstarch.
Stir well until cornstarch dilutes.
In low to medium heat, add this mixture to a pan.
Stir continuously, and cook it until the sauce thickens to the desired consistency.
Notes
Adjust the heat level by reducing or skipping crushed red pepper for a milder version, or add Sriracha, Thai chili paste, or Sichuan chili flakes for extra spice.
Use it as a marinade for chicken, seafood, or tofu, as a stir-fry sauce for vegetables and proteins, or as a dipping sauce for dumplings and spring rolls.
Store in the refrigerator for up to a week or freeze for three months. Reheat on the stovetop or microwave, adding a splash of water if it thickens too much.