1 tablespoon bourbon
1 cup sugar
1 teaspoon baking soda
1 1/2 cups roasted salted peanuts
1/2 teaspoon vanilla extract
2 tablespoons unsalted butter, cut into 1/2-inch cubes
1/2 cup light corn syrup
Line a rimmed baking sheet with a Silpat or greased parchment paper.
Whisk the bourbon, baking soda, and vanilla extract together in a small bowl.
Heat the corn syrup with 1 tablespoon water in a deep, heavy-bottomed pan until steaming and just bubbling at the edges, then add the sugar and stir to dissolve.
When the sugar syrup comes to a boil, cover for 3 minutes to dissolve any sugar crystals that might be clinging to the sides of the pan. Uncover and stir in the peanuts.
Continue to boil until temperature of sugar syrup reaches 300˚ (the hard crack stage) on a candy thermometer. There will be a very slight change in color. Sugar turns from clear to barely golden, almost impercceptible. Use a candy thermometer.
Add the butter and reserved baking soda, bourbon, and vanilla extract and stir vigorously. The brittle will foam up and turn golden.
With the help of a spatula, pour the brittle onto the prepared baking sheet. (Be extremely careful when working with molten sugar!) Work quickly to spread it as evenly as possible.
Allow the brittle to cool and harden completely, about a half hour, before breaking into pieces.