Prepare the chocolate pudding according to package instructions, then refrigerate until set.
In a mixing bowl, combine the peanut butter, powdered sugar, and vanilla extract.
In a separate bowl, whip the heavy cream until stiff peaks form.
Gently fold the whipped cream into the peanut butter mixture until fully combined.
Slice the bananas into thin rounds and set aside.
Start layering in a trifle dish or individual glasses: place ladyfingers on the bottom, followed by chocolate pudding, banana slices, and peanut butter mousse.
Repeat the layering process until the glasses are filled, finishing with the peanut butter mousse on top.
Chill the assembled trifle for at least 2 hours before serving for the best flavor and texture.
Just before serving, garnish with chocolate shavings and extra banana slices, if desired.
