Place sugar and 2 ounces (1/4 cup) water into a small, heavy-bottomed saucepan over high heat. Whisk gently until sugar has dissolved and mixture comes to a rolling boil. If necessary, use a wet pastry brush to remove any sugar crystals from the sides of the pan.
Allow mixture to continue cooking over high heat, WITHOUT STIRRING, until it has reduced slightly and becomes golden amber in color.
Stand back from the pan slightly and carefully add remaining 4 ounces of water. CAUTION: The mixture will pop and sputter as you do this, so please be careful. (Keep a bowl of cold ice water nearby to plunge your hand into should it become burned)
Reduce heat to medium and continue cooking until mixture has reduced slightly and is sticky between your fingers (Let the syrup cool slightly before it touches your fingers so that you don't burn yourself!)
Transfer liquid to a heatproof container. If covered and refrigerated, syrup will stay good indefinitely.