Preheat your oven to 375°F (190°C). Let your large eggs sit at room temperature for about 15 minutes. Prepare a 9-inch round baking pan by greasing it and lining the bottom with parchment paper.

In a large mixing bowl, whisk together the dry ingredients: all-purpose flour, baking powder, baking soda, and pumpkin spice. In a separate bowl, mix the wet ingredients: pumpkin puree, sugar, and the room temperature eggs. Combine both mixtures gently until just combined, then fold in the chopped hazelnuts. Pour the batter into the prepared pan and bake for 25–30 minutes, or until a toothpick inserted comes out clean.

While the cake bakes, prepare your coffee-maple syrup by mixing freshly brewed coffee with maple syrup in a small bowl. Set aside to cool for later use.

In a medium mixing bowl, blend the mascarpone cheese with the cooled coffee-maple syrup and sugar using an electric mixer. Beat until smooth and creamy, about 2-3 minutes.

Once the cake has cooled, slice it horizontally into three equal layers. Drizzle the coffee syrup over the first layer, allowing it to soak in, then spread a layer of mascarpone cream. Repeat with remaining layers, finishing with the top layer of cake.

Spread any remaining mascarpone cream on the top and sides of the cake. Cover with plastic wrap and refrigerate for at least 4 hours, preferably overnight.