In a saucepan over medium heat, melt butter and stir in brown sugar. Let it come to a light boil and simmer for 2 minutes, stirring constantly.

Remove from heat and mix in vanilla extract and baking soda.

In a large mixing bowl, combine Chex cereals and pretzels. Pour the caramel mixture over and toss gently to coat.

Spread the coated mixture on a parchment-lined baking sheet.

Bake at 250°F for 45 minutes, stirring every 15 minutes.

In a small bowl, combine granulated sugar and cinnamon.

Once the mix is out of the oven and still warm, sprinkle the cinnamon-sugar blend over it and toss to coat evenly.

Let it cool completely, then mix in the chopped caramel squares.

Store in an airtight container.