Directions:

Heat oven to 350 F. Grease 13 x 9 x 2- inch baking pan.

In large bowl, beat butter until fluffy. Add sugar; beat on medium speed until light. Stir in egg and vanilla. Add graham cracker crumbs, flour and salt and stir to blend. Set aside 2-1/2 cups of the graham cracker crumb mixture. Press remaining mixture into bottom of prepared pan.

Place chocolate bars side by side (breaking to fit, if necessary) on top of mixture in pan. Sprinkle marshmallows evenly on top of chocolate bars in pan. Crumble reserved graham cracker crumb mixture on top of marshmallows.

Bake 30 minutes. Cool 10 minutes in pan on wire rack. Cut into bars. Cool completely.