Nutty Caramel Chex Mix

7 cups Corn/Rice/Mixture of Chex cereal
1 cup nuts (mixed nuts, cashews, almonds, etc.)
1 cup small pretzels
4 Tbl. (1/2 cube) butter
1 cup packed brown sugar
1/2 cup corn syrup
2/3 cup sweetened condensed milk
1 tsp. vanilla extract

Combine the cereal, nuts, and pretzels in a large, greased bowl.
Preheat oven to 250 degrees.
In medium saucepan over medium-heat, combine butter, sugar and corn syrup.  Cook and stir until the candy begins to boil.
Stir in the sweetened condensed milk.
Use a candy thermometer and continue to cook over medium heat until the mixture reaches 238 degrees.  
Remove it from the heat and stir in the vanilla.
Pour over cereal/nut mixture and stir until all pieces are coated.
Pour mixture onto a large, rimmed baking sheet prepared with silicone mat or non-stick spray.
Bake at 250 degrees for 30 min...stirring every 10 min.
Remove from oven and spread out on wax paper or parchment to cool.