Line a 9x5x3-inch loaf pan with plastic wrap; set aside.
Combine maple syrup and bourbon, set aside
In a small bowl, combine pumpkin, cinnamon, ginger, and salt.
Fold cool Whip into pumpkin mixture.
In another small bowl, combine mascarpone cheese and powdered sugar. Beat on low speed until combined. Gradually beat in the ½ cup whipping cream just until thickened. Do not over beat.
To assemble: arrange half of the ladyfingers in a single layer in the bottom of the prepared pan. Drizzle evenly with half of the syrup. Top with half of the filling, spreading evenly. Arrange remaining lady fingers in a single layer over filling. Drizzle with remaining syrup and top with remaining filling. Dollop topping over filling. Using the back of a spoon, carefully spread topping evenly over filling. Cover and chill 8 hrs or overnight.
Use the plastic wrap to lift tiramisu out of pan. Place on a serving platter. Sprinkle with nutmeg. Carefully cut the dessert into slices.