Preheat your oven to 350°F (175°C) and line a 9x13 baking pan with parchment paper for easy removal after baking.

In a mixing bowl, cream the unsalted butter with granulated sugar and brown sugar until smooth and creamy. Add in the eggs and vanilla extract, mixing until combined.

In a separate bowl, whisk together the flour, cocoa powder, and salt. Gradually mix the dry ingredients into the wet ingredients until just combined, then fold in the chocolate chips.

Pour the brownie batter evenly into the prepared pan, smoothing the top with a spatula. Bake for 30-35 minutes, or until a toothpick inserted comes out almost clean.

In another bowl, beat together softened butter, pumpkin puree, and vanilla until smooth. Gradually add in the cinnamon, nutmeg, and powdered sugar, mixing until creamy.

Once the brownie layer is completely cooled, spread the pumpkin mixture evenly on top and refrigerate for at least 30 minutes.

For the ganache, heat heavy cream until steaming, then pour over chocolate chips in a bowl. Let sit for a couple of minutes, then stir until smooth.

Once the pumpkin layer is chilled, pour the ganache over the pumpkin layer and spread evenly. Return to the refrigerator for another 30 minutes.

Cut the brownies into 24 squares and enjoy.