S'more cooke bars are a soft and chewy graham cracker cookie mixed with gooey, melted marshmallow and chocolate!
In a separate large bowl, cream the butter and sugar together until light and fluffy, about 2 minutes.
Add the eggs and vanilla and beat until well combined. Reduce the mixer speed to low and add the flour mixture, mixing until combined.
Press HALF of the dough mixture evenly into the bottom of the prepared pan.
Dollop the marshmallow creme on top and gently spread into an even layer. If the marshmallow creme gets really sticky you can dip your spoon in hot water (shake off excess water) and it will help to spread it easier.
Break the chocolate bars into pieces and layer over the marshmallow (or sprinkle with chocolate chips). Gently spread the remaining dough over the chocolate.
No need to try and spread the dough into an even layer--the marshmallow and chocolate should peek through!
*Don't substitute regular marshmallows. They will completely dissolve while baking.