Pre-heat oven to 350*F.
In a bowl, mix together your dry cookie ingredients except the sweetener.
In another bowl, beat together the butter, egg white, black food colouring and vanilla extract until mostly smooth.
Next add your sweetener and mix with a spoon first before beating the mixture again to prevent sweetener flying everywhere!
Once this mixture is smooth, you can add it to the dry ingredients. Mix using a spoon until somewhat of a dough begins to form.
Add your water and keep mixing until it's mostly all incorporated.
At this point, things do get a little messy! I use my hands to form the rest of the dough. (I did get all of the black food colouring off my hands right after if anyone is wondering, haha, just don't wear nice clothes during baking).
Once you've formed a solid ball of dough, place it on a flat surface between two sheets of parchment paper and roll it out decently thin (about the thickness of an Oreo as they don't rise a lot!).
This step is optional but you can go around and stamp a regular Oreo into the dough to get your signature logo for each cookie..or just skip this!
Next, cut out circles using a greased shot glass or another small circle about the size of an Oreo around your logos. (I liked to grease mine every couple cookies I cut out). Stamp the glass down firmly and wiggle it back and forth a bit to create the smooth edges..then remove.
Take your cut outs and gently lift them with a spatula and place them on your slip mats or a tray covered in parchment paper.
Remove the excess dough around your cut-outs and roll it out again to repeat the process until all the dough is gone.
Bake the cookies for 8-11min then let them cool on their trays. It's tough to tell when they are done so I recommend doing a test cookie and letting it cool fully if you can. These harden up quite a lot once fully cooled.
While the cookies are baking, you can make your filling by beating together the above 3 filling ingredients. Again, at a certain point I find my hands are the best way to form the mixture into a ball of dough.
I then do the exact same thing I did with the Oreo cookies and roll this dough out between two pieces of parchment paper, then cut circles using a clean, greased shot glass and a clean spatula to lift them (to prevent any black food colouring from getting mixed with the white filling dough). Lift the filling scraps up, and roll it out again if needed.
Set each piece of filling onto a cooled Oreo cookie and top it off with another half of an Oreo cookie. Repeat for all of the cookies. AND THAT'S IT!