01 - Preheat oven to 250°F. Line a large rimmed baking sheet with parchment paper or a silicone baking mat.
02 - Spread oyster crackers evenly over the prepared baking sheet.
03 - In a medium saucepan over medium heat, melt butter. Add brown sugar, corn syrup, and salt. Stir constantly until mixture comes to a gentle boil; let boil for 2 minutes without stirring.
04 - Remove from heat. Immediately stir in baking soda and vanilla extract. The mixture will foam slightly.
05 - Pour the hot caramel mixture over the crackers. Use a spatula to gently toss and coat the crackers evenly.
06 - Bake for 30 minutes, stirring every 10 minutes to ensure even coating.
07 - Remove from oven and allow to cool completely on the baking sheet. The crackers will crisp as they cool. Break apart any clusters and store in an airtight container.