12 tablespoons (1 1/2 sticks) unsalted butter, plus more for cutting
1 cup plus 1 tablespoon heavy cream
1 tablespoon bourbon
2 1/2 teaspoons vanilla extract
2 teaspoons finely grated orange zest
Line a 9 x 9-inch baking pan with parchment paper, leaving an overhang on all 4 sides of the pan. In a 3-quart saucepan, combine the sugar, corn syrup, butter, and 1 cup of the cream. Bring to a boil over medium-high heat, frequently stirring gently, until the butter melts and the sugar dissolves, about 6 minutes. Clip a candy thermometer to the side of the saucepan. Reduce the heat to medium and cook, without stirring, until the mixture registers 248°F on the candy thermometer, 35 to 40 minutes. Remove from the heat.
Meanwhile, in a small bowl, stir together the bourbon, vanilla, orange zest, and remaining 1 tablespoon of cream. Gently stir the bourbon mixture into the caramel mixture, being careful not to scrape down the sides of the saucepan. Pour the mixture into the prepared baking pan, but do not scrape down the sides of the saucepan.
Let cool at room temperature until the caramel is firm and cool, about 2 hours. Using the parchment lining, transfer the caramel to a cutting board. Using a buttered knife or kitchen scissors, cut the caramel into 72 rectangular pieces. Wrap the caramels in wax paper, twisting the ends to seal.
Store in an airtight container at room temperature for up to 2 weeks.