In a deep saucepan over medium heat, add the butter. Once melted stir in the marshmallows and stir with a wooden spoon until melted. Add the peanut butter and vanilla, remove from heat, and stir to combine. Stir in the puffed brown rice cereal and make sure all pieces are evenly coated.
Spoon half of the mixture into a greased 9×9-inch pan and press down with parchment to create an even, flat base. Pour the jam on top and spread an even layer across. Spoon the other half of the peanut butter and crispy rice mixture on top of the jam and push down with the parchment until evenly flat. Place in the refrigerator to cool completely, about 35 minutes. Cut into pieces and serve. Makes 18-20 bars, depending on how large you would like them.