In a large bowl, combine the habaneros, red onion, and garlic. Transfer the habanero mixture to a quart jar with a lid, taking care to gently push the peppers into the jar. Leave ¼ inch (6 mm) of headspace at the top of the jar.
In a small saucepan, combine the remaining ingredients and heat until boiling. Remove from the burner and pour over the onions, pepper