Thaw pastry sheet at room temperature 30 minutes. Preheat oven to 350 degrees F.
Using 1 miniature muffin pan, spoon 1 teaspoon melted chocolate into bottom of each cup. Let cool.
In a medium bowl, combine butter, peanut butter, cracker crumbs, and sugar, stirring well.
Press 1 teaspoon peanut butter mixture over chocolate, pressing to edges of cup. Spoon melted chocolate over peanut butter to cover. Repeat procedure with remaining chocolate and peanut butter mixture. Let cool. Remove from muffin cup
Unfold pastry on lightly floured surface. Roll out into an 18 by 9-inch rectangle. Cut into 9 even pieces. Press squares into the other miniature muffin pan .
Place a peanut butter cup in the center of pastry and top with a few marshmallows. Bake for about 10 minutes or until golden. Cool in pan on wire rack 10 minutes. Remove from pan and cool on wire rack.