Pour your cooled coffee into a shallow dish and whisk in 1 teaspoon of pumpkin spice.
Whip your heavy cream until it forms stiff peaks. Set aside.
Add your mascarpone cheese, pumpkin puree, sugar, and 1 teaspoon of pumpkin spice to a separate bowl. Mix together until smooth and creamy.
Fold the whipped cream into the pumpkin-mascarpone cream.
Dip a lady finger into the coffee and layer into the bottom of an 8x8 casserole dish. Continue dipping lady fingers until the entire bottom of the pan is filled.
Spread half of the pumpkin-cream mixture over the lady fingers.
Build another layer of dipped lady fingers on top of the pumpkin cream.
Spread the remaining cream mixture over the top.
Dust the cocoa powder over the top of the pumpkin tiramisu.
Allow the tiramisu to refrigerate overnight to set up.