Cream the butter and sugar until light and fluffy.

In a separate bowl, beat the egg yolks until creamy. Add the bourbon and nutmeg and beat again.

Add the yolk mixture to the butter mixture until well-combined.

In a clean bowl and using clean beaters, beat the egg whites until stiff. Using a large rubber spatula, gently fold the whipped cream into the butter-yolk mixture, then gently fold in the pecans.

Line the bottom and sides of a large springform pan with ladyfingers. Gently spoon the filling mixture into the lined pan, and use the spatula to even the top. Arrange the remaining ladyfingers attractively over the top, pressing lightly into the filling. Wrap the cake with plastic wrap and transfer to the refrigerator until thoroughly chilled and the filling has set up, at least 4 hours and up to overnight.

Place the whipping cream in a large bowl along with the remaining powdered sugar and vanilla and whip until stiff but not dry. Spoon enough of the whipped cream onto the top of the cake to cover well. Serve the cake immediately, or within several hours. Pass any remaining whipped cream on the side or garnish slices with an additional dollop if desired.