Pour the vegetable oil into a medium-sized saucepan and heat it on high.
Add the garlic, ginger, and chilis to the saucepan. Stir them continuously and cook for about 15 seconds until they start to smell good.
Mix in the soy sauce, chicken broth, vinegar, brown sugar, sesame oil, and red pepper flakes. Let it come to a boil, then lower the heat to medium and cook for 1 minute.
Mix the water and cornstarch together until it dissolves completely, then pour it into the sauce. Stir the sauce continuously while cooking until it becomes thicker.
Allow to cool for about 1 hour. Then, put it in a container that can be sealed tightly and keep it in the refrigerator for up to 4 days. When you want to warm up the sauce, heat it slowly over low heat.