Wash and dry the apples, remove their stems and stick a wooden skewer into the stem end of each one. Set the skewered apples aside.
In a small saucepan, combine sugar, syrup, cream and butter and place over high heat. Bring to a boil and boil for 3 to 5 minutes, or until mixture registers 245°F on a candy thermometer. Remove from heat and swirl in the vanilla.
Quickly dip the apples, one at a time, into the caramel, and spoon extra over the apples to cover completely. Hold the skewer between the palms of your hands and spin for a moment to cool. Place upright on waxed paper.