In a small saucepan, heat the cream just until small bubbles appear around the edge. In a medium saucepan, cook the sugar with the water over high heat until the sugar is dissolved, washing down the side of the pan with a wet pastry brush. Continue cooking, without stirring, until a light honey-colored caramel forms, about 5 minutes. Remove from the heat and carefully stir in the scalded cream. Let cool for 1 minute, then stir in the vanilla. Serve warm.
The caramel sauce can be refrigerated in an airtight container for up to 1 week.