Preheat your oven to 180C / 355F (fan off), 160C / 320F (fan on). Spray a 20cm / 8-inch square cake tin with oil spray. Line the bottom and sides with baking paper leaving some overhand to make taking it out easier. I like using bulldog clips to keep the paper in place.
Cream butter and sugar - Add the butter, sugar, salt and brown sugar into a large mixing bowl. Use an electric hand mixer to cream together, about 2 minutes.
Add eggs and vanilla - Scrape down the bowl and add the egg, egg yolk, vanilla extract and orange zest and mix until well combined.
Add dry ingredients - Scrape down the bowl and add the flour, baking powder and cinnamon and use a spatula to mix until a dough forms.
Add crackers and chocolate - Next, add 100g of the chopped graham crackers and 200g of the chopped chocolate and mix in. The rest is for the top!
Bake - Add half of the cookie batter to the bottom of the cake tin and spread evenly across the bottom. Then pour in the marshmallow fluff (see notes) on top and spread out evenly. Finish by adding little pieces of the remaining dough around along with the remaining graham crackers and ark chocolate. Bake for 20-25 minutes. Once baked, allow to cool to room temperature. Then chill in the fridge for at least 2 hours to firm up before slicing into 9 squares using a large knife.
Video
Notes
Graham crackers - If you’re in an area where graham crackers aren’t sold, you can basically use any type of vanilla cookie. You want to chop them, not crush them. I would recommend chopping them much finer than I did in the video otherwise you’ll need to use a spoon to chop them as you spread the batter around. Use the larger chunks for the top.Dark Chocolate - Make sure you use good quality chocolate. Anything with a cocoa content percentage of 70% will work. I used the Lindt chocolate.Marshmallow fluff - Making your own marshmallow fluff is really easy. I have a great recipe for it here!Storage - These S’mores Cookie Bars can be stored in an airtight container for up to three days.Nutrition - is based on per bar. This recipe makes 9 bars.