Preheat oven to 375°F. Line a 10x15 jelly roll pan with foil and spray with nonstick cooking spray for easy removal.
Make the caramel ganache: place caramels and heavy whipping cream in a medium microwave safe bowl. Heat on high power in 30 second increments, stirring between each, until melted and smooth. Chill until set, a few hours. While the caramel is chilling, make the cake and filling.
Beat eggs at high speed for 4 minutes, or until the eggs are thick and dark yellow and foamy. Mix in sugar until combined. Add pumpkin, lemon juice, baking powder, spices, and salt, mix until combined, then slowly mix in the flour, scraping the sides of the bowl as needed.
Place cake batter in prepared pan and speed into an even layer. Bake for 11-15 minutes or until it somewhat bounces back when you lightly press it (and the top of the cake doesn’t stick to your fingers). A toothpick will come out clean.
While the cake is in the oven, lay out a clean kitchen towel and sprinkle it liberally with powdered sugar. Remove the hot cake from the oven and immediately flip it over (careful not to burn yourself) and remove the pan and foil. Roll up the cake using the towel. Let sit at room temperature to cool, about 2-3 hours.
Make the filling: beat cream cheese until creamy, then mix in sugar until smooth. While the mixer is running, add the heavy whipping cream slowly and then the vanilla. Turn the mixer up and beat until the mixture has turned into whipped cream with stiff peaks.
Finish the caramel by removing it from the refrigerator and beating it with a hand mixer until it’s spreadable. It will change in color and consistency.
Assemble the cake: carefully unroll the cake from the towel. It may crack, but that’s okay, just be gentle. (Mine cracked but you couldn’t tell!) Spread a thin layer of caramel on the cake, then top with a hefty helping of the filling. Re-roll the cake, removing it from the towel as you go. (It may stick a little). Wrap the cake in plastic wrap and chill at least one hour before serving.