Preheat the oven to 350°F (175°C). Line a baking sheet with parchment paper.
In a small bowl, mix granulated sugar and ½ teaspoon pumpkin pie spice. Set aside.
In a medium bowl, whisk together flour, 1 tablespoon pumpkin pie spice, baking soda, baking powder, and salt.
In a large bowl, beat butter and brown sugar until light and fluffy. Add egg yolks, vanilla, and dried pumpkin. Mix well.
Gradually add the dry ingredients to the wet ingredients, mixing until combined.
Scoop dough into balls, roll in the spiced sugar mixture, and place on the baking sheet. Flatten slightly.
Bake for 10-12 minutes. Let cool on the baking sheet for 5 minutes, then transfer to a wire rack.
For the coffee mascarpone cream, whip heavy cream until stiff peaks form. Add mascarpone, espresso powder, vanilla, powdered sugar, and pumpkin pie spice. Mix until smooth.
For the ganache, heat heavy cream and espresso powder until steaming. Pour over chopped white chocolate. Let sit for 2 minutes, then stir until smooth.
Spread mascarpone cream on cooled cookies and drizzle with ganache.
Notes
Store cookies in an airtight container in the refrigerator for up to 3 days.