In a small saucepan, combine all ingredients except cornstarch and water.
Bring to a simmer.
Cover and simmer for 10 minutes.
Remove from heat.
Using a slotted spoon, discard garlic.
Dissolve cornstarch in water and stir into sauce.
Simmer, stirring constantly, until sauce thickens slightly, about 2 minutes.
Transfer to a small bowl; cover and refrigerate until thoroughly chilled.
Use as a dipping sauce for Spring Rolls.