In a large bowl, combine 2 cups of creamy peanut butter, 2 cups sugar and two eggs.
Drop by tablespoonful onto well-greased baking sheets. Sprinkle with remaining sugar, and lightly press a criss-cross pattern with a fork.
Bake for 8 to 10 minutes, or until edges are golden brown and centers are set.
Allow to cool on baking sheets for 1 to 2 minutes before transferring to a wire rack to cool completely.
Meanwhile, in a large mixing bowl, beat the marshmallow fluff, slowly adding powdered sugar until the mixture is ultra thick and can be formed into 1-inch balls. You want it thick enough that the marshmallow fluff won’t be runny.
Press the ball of marshmallow frosting onto the bottom of one cookie. Spread the bottom of another cookie with about 1 tablespoon peanut butter. Smash the cookies together to form cookie sandwiches.
