Preheat oven to 350°F/175°C. Line cookie sheet with parchment paper or baking mat.
Using a standing mixer, cream together the butter, powder sugar, vanilla and egg together until creamy and combined.
In a large bowl, mix together the flour, cream of tarter and baking soda. Gradually mix the flour mixture into the wet ingredients until combined and a dough forms.
Once the dough is formed, sprinkle about 3 tablespoons flour onto surface. Place the dough onto the floured surface and sprinkle some flour onto the dough. Roll out the dough to about 2 inches thick. Cut out your cookies and place onto the cookie sheet.
Bake for about 8-10 minutes. Let them cool completely.
Royal icing directions:
Using a standing mixer, combine all icing ingredients and mix on medium to high speed until thick and stiff with peaks about 6-7 minutes. If your icing looks like yellow soup, add another cup of powder sugar.
Scoop some white icing into one piping bag and set aside.
Scoop some icing, about 3/4 up, into a bowl and add black food coloring and mix until combined. Scoop the black icing into piping bag.
Using the remaining icing, add in red food coloring and mix until combined. Add in a few more drops of red food coloring to get the shade you want. Scoop a small amount into the piping bag and set aside. Mix in 2-3 tbsp of water into the remaining red icing and mix until combined. Pour into the squeeze bottle.
Decorating directions:
Using the red icing, outline the mickey heads. Fill in the cookies with the thinned red icing. Let them dry completely over night.
Once they have completely dried, use the black icing to pipe on the outline of the mask and the eyes.