Method
1. Prep
Line a baking sheet with parchment paper.
2. Cook the Toffee
Combine the butter, brown sugar, salt, and vanilla in a small saucepan over medium heat. Stir constantly. Cook time varies by stove, but the mixture is ready once it reaches the consistency of melted peanut butter.
3. Test for Doneness
Drop a small amount of the toffee into cold water and bite down on it. If it hardens and crunches, it's done.
4. Cool and Break
Pour the toffee onto the prepared baking sheet, spreading it into an even layer. Cool completely, then refrigerate until fully hardened. Break into bits.
Cook's Notes
Pan Use a heavy-bottomed saucepan and stir constantly to avoid scorching.
Storage Airtight container, up to 1 month at room temp or 3 months in the freezer.