1
Preheat oven to 350°F. Grease a baking pan with nonstick cooking spray. Add butter and sugars to a stand mixer with the paddle attachment. Beat for 2-3 minutes.
2
Next, add the egg and vanilla and mix until combined.
3
Meanwhile, mix flour, graham cracker crumbs, baking soda, and salt in a bowl.
4
Add the ingredients to the stand mixer and mix until combined. Be careful not to over mix this!
5
Press the dough in the bottom of the greased pan and bake for fifteen minutes. Be careful not to overcook the dough.
6
Finally, add the marshmallows and chocolate to the cooked dough. These s'mores bars are going to be soo good!
7
Cover the marshmallows with the remaining dough. It's okay if the dough does not cover the entire surface of the marshmallows.
8
Bake fifteen more minutes or until lightly browned. Allow the bars to cool on a wire rack before cutting. They are crumbly and hard to get to if they are warm.