In a sauce pot over low-medium heat, add avocado oil. Add the onion and garlic and sauté until fragrant and softened. Do not over-brown.
1 small white onion, ¾ tbsp avocado oil, 5 fresh garlic cloves
Add water, bay leaves, and whole peppercorns. Bring to a gentle low simmer for 2 minutes.
1½ cups water, 4 bay leaves, 1 tsp whole black peppercorns
Then, stir in soy sauce, brown sugar, and vinegar. Keep heat at low to medium and cook for 10–12 minutes. Do not boil.
½ cup soy sauce, ⅓ cup cane vinegar or white vinegar, 2¼ tbsp brown sugar
Add the cornstarch slurry. Bring to a medium-high simmer and cook for about 3 minutes, stirring constantly to avoid burning.
Cornstarch slurry: 1 tbsp cornstarch and 1 tbsp cold water (mix well)
Remove from heat. Pour the sauce through a wire mesh strainer into a bowl to create a smooth base. Add back a small scoop of the strained solids for texture, along with 1 bay leaf and a few peppercorns.Let the sauce cool down. Once refrigerated, it will slightly gel—that’s normal. It loosens back into a smooth, silky sauce when reheated.