CHOCOLATE-CARAMEL SWISS ROLL

Steps:

• Whipped cream: Fill a large bowl with ice water. In a small, heavy pot, stir together granulated sugar and 2 tablespoons water; heat over medium-high, stirring occasionally, until sugar is dissolved. Continue to cook, swirling occasionally, until deep golden brown, about 6 minutes. Meanwhile, stir cornstarch into 1/4 cup cream, then stir mixture into remaining 1 1/4 cups cream. Add cream mixture and salt to caramel, whisking constantly (it will bubble up), and bring to a boil. Set pot in bowl of ice water and let cool, whisking occasionally, 30 minutes; then refrigerate until very cold, at least 1 hour and up to overnight.
• Cake: Preheat oven to 425 degrees. Spray a 12 1/2-by-17 1/2-inch rimmed baking sheet with cooking spray. Line with parchment; spray parchment, then dust with cocoa, tapping out excess. Whisk together cocoa, flour, and salt.
• Combine eggs, yolks, and granulated sugar in a heatproof bowl set over (not in) a pot of simmering water. Whisk until sugar is dissolved and mixture is warm to the touch, about 2 minutes. In a mixer fitted with the whisk attachment, beat on medium-high speed 2 minutes. Increase speed to high and beat until mixture is pale and thick, about 4 minutes more.
• Sift cocoa mixture over top of egg mixture, then fold in. When almost incorporated, pour butter down side of bowl; gently fold to combine, scraping bottom of bowl. Transfer to prepared sheet, using an offset spatula to spread evenly. Bake until center springs back when lightly touched, 6 to 7 minutes. Run a small sharp knife around edges of cake. Invert onto a clean kitchen towel; remove parchment. Immediately, starting at one short side, roll into a log, incorporating towel. Let cool 30 minutes.
• Syrup: In a small, heavy pot, stir together granulated sugar and 2 tablespoons water; heat over medium-high, stirring occasionally, until sugar is dissolved, 1 minute. Continue to cook, without stirring but swirling occasionally, until syrup turns dark amber, 3 to 4 minutes. Whisk in 1/4 cup water (it will bubble up), bourbon, and cocoa. Whisk until smooth. Let cool about 30 minutes.
• Whisk confectioners' sugar into chilled cream mixture, then whip to stiff peaks. Refrigerate at least 30 minutes and up to 2 hours. Whisk again just before filling cake.
• Unroll cooled cake. Brush surface generously with syrup. Use offset spatula to spread whipped cream over cake, leaving a 1/2-inch border all around. Starting at a short end, roll cake to enclose filling (without towel). Wrap towel around cake (for a tight roll, hold closed with binder clips). Refrigerate at least 1 hour and up to overnight. Dust with cocoa and serve. (For cleanest slices, use a serrated knife.)