Preheat the Oven:
Preheat your oven to 350°F (175°C). Grease and line two 9-inch round cake pans with parchment paper.
Make the Pumpkin Cake Layers:
In a medium bowl, whisk together the flour, baking powder, baking soda, cinnamon, ginger, nutmeg, cloves, and salt.
In a large bowl, whisk together the granulated sugar, brown sugar, oil, and pumpkin puree until smooth.
Add the eggs one at a time, whisking well after each addition, and then stir in the vanilla extract.
Gradually add the dry ingredients to the wet mixture, alternating with the milk, beginning and ending with the dry ingredients. Mix until just combined.
Divide the batter evenly between the two prepared cake pans.
Bake for 25–30 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cakes to cool in the pans for 10 minutes, then transfer to a wire rack to cool completely.
Make the Salted Caramel Sauce (if making from scratch):
In a medium saucepan, heat the sugar over medium heat, stirring constantly with a wooden spoon until the sugar melts into a golden-brown liquid.
Add the butter and stir until it melts completely and is fully incorporated.
Slowly pour in the heavy cream while continuing to stir. The mixture will bubble up, so be cautious.
Boil the mixture for about 1 minute, then remove from heat and stir in the sea salt.
Let the caramel cool slightly before using. (Store extra caramel in the fridge for future use.)
Make the Salted Caramel Buttercream:
In a large mixing bowl, beat the softened butter until light and fluffy, about 2–3 minutes.
Add the salted caramel sauce and beat until fully incorporated.
Gradually add the powdered sugar, 1 cup at a time, while beating on low speed.
Add the sea salt and 2–3 tablespoons of heavy cream, and continue beating until the frosting is smooth, fluffy, and spreadable.
Assemble the Cake:
Once the cake layers have cooled completely, place one layer on a serving plate or cake stand.
Spread a generous layer of the salted caramel buttercream over the top.
Place the second cake layer on top and frost the top and sides of the cake with the remaining buttercream.
Drizzle with Extra Salted Caramel:
For extra flair, drizzle the top of the cake with more salted caramel sauce, allowing it to drip down the sides for a beautiful effect.