Add low-sodium soy sauce, 1 cup water, ground ginger, crushed garlic, brown sugar (adjust according to your sweetness preference), and chilli flakes to a saucepan. Heat on high heat for 2 - 3 minutes.
Once your mixture starts to heat up and slowly bubbles on the sides, turn the heat down to medium-low before adding in the slurry you made.
Mix the corn flour and cold water until they are combined and there are no lumps. This will help thicken the sauce.
Let it simmer until it thickens and turns glossy. This should take 4 - 5 minutes at most.
If it is too thick, you can thin it out with water, but only add a little, around 1 - 2 Tbsp.
Let it cool, then mix it quickly before bottling and storing it in the fridge.
