Preheat oven to 250°F (120°C). Line a large baking sheet with parchment paper.

In a medium saucepan over medium heat, combine sugar, butter, corn syrup, and water. Stir until sugar dissolves.

Bring to a boil, stirring occasionally, until the mixture turns a deep amber color (about 5-7 minutes). Remove from heat.

Quickly stir in baking soda and vanilla extract. It will bubble up.

In a large bowl, combine popcorn and cake mix.

Pour the caramel over the popcorn mixture and stir to coat evenly.

Spread the caramel corn in a single layer on the prepared baking sheet.

Bake for 45 minutes, stirring every 15 minutes, until golden brown and crispy.

Remove from oven and immediately sprinkle with white chocolate chips.

Let cool completely on the baking sheet before breaking apart and serving.