Before you begin, place two pieces of parchment paper on two baking sheets and set them aside.
Pour the box of Rice Chex Cereal into a large bowl and set it aside.
Next, place the butter, light brown sugar, salt, and corn syrup in a medium saucepan and place over medium-high heat.
Allow it to boil for about a minute. The longer you let the caramel mixture boil, the harder and crunchier it will become.
Remove from the heat and add the baking soda. The mixture will foam a bit, but it will settle down.
Pour the mixture over the Rice Chex Cereal and stir until all the cereal is covered.
Next, place the mixture in the microwave for one minute. Then, remove it and stir. Repeat this process twice more stirring it between each minute.
After the third time you stir it, pour half onto each baking sheet and allow it to cool completely.
Break the Caramel Chex Mix apart and store in it an airtight container. The Caramel Chex Mix will stay fresh for five days.