Best Caramel Apple Dip

I got this yummy Caramel Apple Dip from a friend of mine and had to get the recipe.  I hope you like it.

Melt together over medium heat:
1 C. butter
2 C. brown sugar

Add:
1 can sweetened condensed milk
1 C. Karo syrup

Continue cooking, stirring constantly, until it barely starts to boil. (First bubbles
appear)

Take off heat and stir in:
1 T. vanilla

Serve warm with apple slices. Keeps well in refrigerator. (Seldom lasts long
enough to worry about spoiling!)

At this point you can put it in little pint jars to give away as a gift, or place it in a container and store in your refridgerator.  This is the best!!