Mix graham cracker crumbs with melted butter. Place a sheet of parchment paper into the bottom of a square 8" x 8" baking pan, and then press the graham cracker mixture into the bottom of the pan to make the crust. Cream the softened butter, add in the sugar and brown sugar, and cream until fluffy. Mix in egg and vanilla. Combine the flour, baking soda, and salt. Mix well. Add the flour mixture to the butter-sugar mixture and combine. Fold in chocolate chips and marshmallows. Spoon the mixture on top of the graham cracker crust (try to make it as even as possible, although it won’t be perfect). Bake for 20 minutes. While the cookie bars are baking, break the chocolate bar into pieces and place it in the freezer. About 8–10 minutes before the cookie bars are finished, you can sprinkle extra marshmallows over the top. Then let the cookie bars finish baking. When done, place pieces of chocolate bar on the top. Let the cookie bars cool completely before cutting. **Great for when you just want something different from regular s’mores.
