Heat oven 350 and grease 8 by 8 pan.

Beat butter and sugar. Add in egg, vanilla.

Combine flour, graham cracker, baking powder, salt. Add mixture to butter mixture.

Press half of the dough mixture into the pan. Arrange chocolate bars on top. Pour marshmallow cream and top with the rest of the dough. Carefully pressing dough on top.

Bake 35 minutes. Allow to cook in the pan prior to cutting. Makes about 20 smaller bars.

Marshmallow creme: In a double boiler, melt marshmallows and corn syrup.