For the Chocolate Cake:

• 2 oz unsalted butter, at room temperature
• 1.75 oz granulated sugar (1/4 cup)
• 1.75 oz brown sugar (1/4 cup)
• 1 large egg, at room temperature
• 1 tsp vanilla extract
• 4 fl oz buttermilk (1/2 cup), at room temperature
• 2.66 oz all-purpose flour (2/3 cup)
• 1 oz unsweetened cocoa powder (1/3 cup)
• 1/2 tsp baking soda
• 1/4 tsp salt

For the Pumpkin Cinnamon Mousse Layer:

• 9 oz cinnamon chips
• 1 1/2 cups heavy cream, divided use
• 1/3 cup canned pumpkin puree
• Pinch of salt
• 2 tsp unflavored powdered gelatin
• 2 tbsp water
• 1 tsp ground cinnamon

For the Pumpkin Butterscotch Mousse Layer:

• 9 oz butterscotch chips
• 1 1/2 cups heavy cream, divided use
• 1/3 cup canned pumpkin puree
• Pinch of salt
• 2 tsp unflavored powdered gelatin
• 2 tbsp water

For the Salted Caramel Mousse Layer:

• 9 oz salted caramel chips or white chocolate chips
• 1 1/2 cups heavy cream, divided use
• 1/3 cup thick salted caramel sauce
• Pinch of salt
• 2 tsp unflavored powdered gelatin
• 2 tbsp water
• 1 tsp vanilla extract

For the Chocolate Ganache on Top:

• 1/2 cup heavy cream
• 3 oz semi-sweet chocolate, finely chopped

To Decorate:

• Whipped cream
• Ground cinnamon
• Candy of your choosing, like pumpkin-shaped truffles