How to Make It
In a small saucepan, combine the sugar, water and lemon juice. Cook over moderately high heat until a golden brown caramel forms, 8 to 10 minutes; occasionally wash down the side of the pan with a wet pastry brush. Off the heat, carefully stir in the cider vinegar. Add the vanilla bean and cardamom pods and let steep for 20 minutes. Strain into an airtight container and let cool completely, then refrigerate for up to 2 weeks.