Continue to cook, without stirring, until mixture is a medium amber color, 8 to 9 minutes.
Remove from heat, and immediately add heavy cream and butter (mixture will boil and foam).
Whisk until well blended, and whisk in salt.
Credit: Alison Gootee; Styling: Suzonne Stirling
Transfer to a bowl, cover with plastic wrap, and chill until cold, about 4 hours.
Meanwhile, prepare the Cake Layers: Place oven rack in center of oven; preheat oven to 350F.
Add pumpkin mixture to flour mixture; whisk gently until just blended but no lumps remain.
Divide batter between prepared pans.
Cool Cake Layers in pans 20 minutes, and transfer from pans to a wire rack.
Cool completely, about 1 hour.
Add butter and beat on medium speed until creamy, about 1 minute.
Add powdered sugar, heavy cream, vanilla, and salt.
Chill 30 to 45 minutes before assembling cake.
Place 1 Cake Layer, top side up, on a cake plate.
Dollop with about 12 cup of the Frosting, and spread evenly.
Top with second Cake Layer, top side up, and dollop with another 12 cup of Frosting.
Spread top and sides with a thin layer of Frosting.
Take Caramel out of refrigerator, and let stand 20 minutes.
Generously swirl Caramel into remaining Frosting, keeping swirls large in mixture.
Spread along top and sides of cake in a few swoops so it looks rustic.
Chill 1 hour before slicing and serving.
