Place the cornstarch in a 1-quart saucepan and stir in the soy sauce to make a smooth, thin paste. Gradually whisk in the water and garlic granules. Place the saucepan over medium-high heat and cook the gravy, stirring constantly with a wire whisk until it thickens and comes to a boil. Remove the saucepan from the heat, and beat the tahini into the gravy using the wire whisk. Cover the saucepan and set aside.
Recipe from Vegan Vittles by Joanne Stepaniak.