Preheat the oven to 350°F. Crush the Nilla wafers in a food processor until they turn into fine crumbs.
Mix the melted butter with the Nilla wafer crumbs, then pour the mixture into a lined baking pan.
Spread and firmly press the Nilla wafer mixture evenly across the bottom of the pan. Bake for 8 minutes.
Let the crust cool slightly, but keep the oven at 350°F.
To make the cheesecake filling, beat the cream cheese and sugar in a stand mixer until smooth and creamy.
Add the eggs and vanilla extract, mixing until fully combined.
Stir in the marshmallow fluff, then add 1/4 cup of peanut butter and mix well.
Continue mixing until everything is fully incorporated and no streaks remain.
Pour the filling over the cooled crust and spread it evenly.
Microwave 1/4 cup of raspberry jam for 30 seconds. Spoon it over the peanut butter cheesecake, then gently swirl it in with a toothpick.
Bake for 20 minutes, then reduce the oven temperature to 200°F. Bake for another 30 minutes.
Turn off the oven and let the peanut butter and jelly bars sit in the pan for 10 minutes, then remove them to cool completely at room temperature.
Once the bars have cooled, microwave the remaining raspberry jam for 30 seconds and pour it over the top. Spread it out evenly.
Microwave the remaining peanut butter for 30 seconds. Transfer it to a piping bag and drizzle it over the bars.
Cover and refrigerate for at least 3 hours before slicing into bars. Enjoy!