Freeze the marshmallow fluff

• Line a baking sheet with parchment paper.
• Scoop dollops of marshmallow fluff onto the sheet, spaced apart.
• Freeze until firm.

Make the cookie dough

• In a mixing bowl, combine the peanut butter, egg and sugar.
• Mix well until a dough forms.
• Divide the dough into equal pieces.

Stuff the cookies

• Press each piece of dough flat.
• Place a frozen marshmallow fluff dollop in the center of each.
• Wrap the dough around the dollop to cover it completely.

Chill the cookies

• Arrange the stuffed cookies evenly apart on a parchment-lined baking sheet.
• Let them set in the freezer.

Bake

• Bake at 175 °C until the cookies are set and lightly golden.
• Let cool completely before serving.