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