Step 1: Prepare Your Workspace - Line a baking sheet with parchment paper.
Step 2: Combine Ingredients - In a heavy-bottomed saucepan, combine the unsalted butter, dark brown sugar, heavy whipping cream, light corn syrup, and kosher salt. Stir over medium heat until the butter melts.
Step 3: Cook the Mixture - Attach your candy thermometer and cook until the mixture reaches 240°F (115°C).
Step 4: Remove from Heat - Let it sit for about 5 minutes without stirring.
Step 5: Add Vanilla and Peanuts - Stir in the vanilla extract and salted cocktail peanuts.
Step 6: Drop onto Parchment - Drop spoonfuls of the mixture onto the prepared parchment paper.
Step 7: Let Cool and Serve - Allow to cool completely before enjoying.