Place the mascarpone in a large bowl and stir to loosen. Set aside.

In a double broiler or heatproof bowl set over a small pot of simmering water, whisk the egg yolks and sugar together. Continue whisking until mixture begins to bubble and thicken, about 5 minutes or 170°F. Remove from heat and continue to whisk for 2 minutes to cool down.

Pour yolk mixture into bowl with mascarpone and stir, just until combined. Gently fold in the pumpkin and pumpkin spice.

In a separate bowl, whip the cream and powdered sugar until stiff peaks form. Fold into the mascarpone pumpkin mixture.

Place the coffee into a shallow bowl and dip the lady fingers in, turning to coat. Line the espresso dipped ladyfingers in a single layer in a 13x9 pan. Top with half the pumpkin mixture. Repeat another layer of espresso-dipped ladyfingers and top with the rest of the pumpkin mixture. Cover and refrigerate for at least 4 hours, preferably overnight. Dust with pumpkin spice before serving.