Preheat the oven to 350°F. Line a jelly roll pan (about 10x15 inches) with parchment paper, leaving some overhang on the long sides for easy lifting.
In a medium bowl, whisk together the flour, cocoa powder, baking powder, and salt until evenly combined.
In a large mixing bowl, beat the eggs and granulated sugar with an electric mixer on medium-high speed until thick, pale, and ribbony, about 5 minutes. Beat in the vanilla bean paste.
Gently fold the dry ingredients into the egg mixture with a rubber spatula just until no streaks of flour remain, taking care not to deflate the batter.
Pour the batter into the prepared pan and spread it into an even layer, smoothing it into the corners.
Bake for 12 to 15 minutes, or until the cake springs back when lightly pressed in the center.
While the cake bakes, lay a clean kitchen towel on the counter and generously dust it with powdered sugar.
Remove the cake from the oven and let it cool in the pan for 2 to 3 minutes, then run a knife around the edges if needed and carefully invert the cake onto the prepared towel. Peel off the parchment paper.
Starting from a short end, roll the warm cake up in the towel into a tight but not squeezed spiral. Place the rolled cake seam-side down on a rack and let it cool completely.
In a small saucepan over low heat, warm the caramel sauce until fluid but not boiling. Add the chocolate chips and stir constantly until fully melted and smooth. Remove from heat and let cool to room temperature but still spreadable.
In a chilled mixing bowl, whip the heavy whipping cream and 2 tablespoons powdered sugar with an electric mixer on medium-high speed until stiff peaks form.
Gently fold half of the cooled caramel-chocolate mixture into the whipped cream until evenly combined, reserving the remaining half for topping.
Once the cake is completely cool, carefully unroll it from the towel so it lies mostly flat. Spread the caramel whipped cream evenly over the surface of the cake, leaving about 1/2 inch clear around the edges.
Re-roll the cake without the towel, starting from the same short end, keeping the roll snug and even. Place the cake roll seam-side down on a serving platter.
Wrap the cake roll tightly in plastic wrap and refrigerate for at least 1 hour to set.
Before serving, remove the plastic wrap, drizzle the reserved caramel-chocolate mixture and extra caramel sauce over the top, and slice with a sharp serrated knife into thick spirals.