In a medium pot, bring sugar, corn syrup, and 2 tablespoons water to a boil over medium-high heat. Cook, stirring occasionally, until mixture reaches a deep amber color, 8 to 10 minutes.
Remove from heat and whisk in condensed milk and butter. Whisk vigorously until smooth. Return to medium-low heat and cook until a candy thermometer registers 240°. Remove from heat and whisk in bourbon, vanilla, and sea salt. Pour into cooled Walnut Crust and let stand until completely set. Add walnuts in an even layer on top of cooled caramel.
Place chocolate in a medium heatproof glass bowl. In a small pot, bring cream to a simmer over medium heat. Pour cream over chocolate. Whisk until smooth. Pour chocolate mixture over walnut layer and let cool completely. Serve with whipped cream and toasted walnuts. Garnish with sea salt, if desired.
Recipe by Southern Lady Magazine at https://southernladymagazine.com/bourbon-caramel-chocolate-tart/