Endlessly Adaptable Stir-Fry Sauce

Ingredients

• 1/2 teaspoon potato starch or cornstarch
• 1/2 cup really good chicken stock, vegetable stock, or an appropriate mock stock such as mock chicken, dried shrimp, or mushroom, or as needed
• 1/2 teaspoon soy sauce
• 1/4 teaspoon sugar
• pinch of freshly ground black pepper or a pinch of finely ground white pepper (if black specks seem inappropriate for the dish)