Preheat your oven to 350 degrees F (175 degrees C). Line an extra-large rimmed baking sheet with aluminum foil and cover it with parchment paper.

Spread the oyster crackers evenly in a single layer on the prepared baking sheet.

In a small bowl, combine 1 teaspoon of ground cinnamon, granulated sugar, and kosher salt. Set aside.

In a small heavy-bottomed saucepan over medium heat, melt the butter and stir in the brown sugar. Bring to a boil and allow it to boil for 2 minutes, stirring occasionally. Remove from heat and stir in vanilla extract and the remaining 1 teaspoon of ground cinnamon.

Pour the hot toffee mixture evenly over the oyster crackers and gently toss to coat.

Bake for 10 minutes or until bubbly and golden.

Remove from the oven and immediately sprinkle the reserved cinnamon sugar mixture over the warm crackers.

Allow to cool completely on the baking sheet, then break apart any large clusters.