Heavily butter a Silpat sheet or parchment paper. Set aside.
Insert the sticks into cleaned apples.
In a 2qt heavy saucepan, combine the butter, brown sugar, corn syrup & sweetened condensed milk. Bring to a boil over medium heat.
Cook & stir until a candy thermometer reads 248 degrees (firm ball stage) This should take about 30-40 minutes depending on the BTUs of your stove.
Remove from heat and carefully stir in the vanilla extract.
Working quickly, dip each apple in the caramel & turn to coat.
Holding by the stick you can sprinkle with whatever topping you like. OR you can set aside on the Silpat to cool. Be sure to work quickly if sprinkling as the caramel will set fast.
While caramel is setting, melt the chocolate chips in a small bowl by microwaving in 30-second increments - stirring in between each time.
Dip the caramel-coated apples in the melted chocolate to coat.
Immediately sprinkle with peanuts & then set back on the Silpat.
Transfer to the refrigerator to cool & harden before serving.