Turn the burner on to medium-high heat. Then — this is very important — do not stir or touch the pan until the sugar has caramelized! The sugar mixture will go from being completely clear, to a champagne color, to a light golden color, and then to increasingly darker shades of amber. (Keep a close eye on the sugar, as it darkens quickly once it begins to caramelize.) Once the sugar reaches a deep amber color (about the color of a copper penny), remove the saucepan from the heat and turn the burner off.