Add egg and vanilla to butter mixture and mix together until smooth.
60 grams egg, ½ teaspoon pure vanilla extract or vanilla bean paste
Slowly spoon in flour mixture on medium speed until dough consistency has been formed.
Remove dough from bowl and form into a ball with your hands. It may be a little sticky but just mold it into shape and don't worry it will firm in the fridge.
Cut dough in half and wrap each section with plastic wrap.
Place in refrigerator to chill for 2 hrs.
*(Dough can be made and kept in fridge over night. You will need to set it out on counter for about 30 minutes before rolling) *
Bake & assemble
Preheat oven to 350℉ (180℃). Line a large cookie sheet with parchment paper.
Remove one dough half from fridge and work with your hands a few times to make it pliable. After sitting in the fridge it may be a little hard, but the warmth from your hands will make it easy to manipulate. Roll out onto a floured surface to 1/8-inch thickness.
Take solid cookie cutter and cut out cookie shapes using up entire dough. These will be the bottoms of your sandwich.
Place on Parchment paper lined tray and bake for 10-12 min or until lightly golden. (I found that 10 minutes worked perfectly for my oven.)
Place bottom cookies on cooling rack to cool completely.
Now remove your second half of dough and repeat with large cookie cutter. Then take smaller shape and cut out the centers of each cookie.
(You can keep the small center pieces and make small cookies or add them back to the scraps, roll out and make larger cookies).
Be sure to bake an even number of top and bottom cookies. Once all cookies are cooled it is time to assemble.
Sprinkle your top cookies without the center with a light dusting of powdered sugar. Spoon a teaspoon of apple butter onto the middle of your bottom cookies. Place the top cookie onto the apple butter.