To make the cookies: Add all of the ingredients to a medium-size bowl and mix until it forms a pliable dough. Set aside in an airtight container in the fridge to chill for at least 20 minutes.
When you are ready to bake the cookies, preheat the oven to 180°C (350°F).
Place the dough on a lightly floured surface. Roll out with a rolling pin so the dough is about 8mm (0.3 inch) thick, Use a circular cookie cutter to cut out circles in the dough. Cut each circle in half to form semi-circles. Carefully place the semi circles onto a lined baking tray with a little space in between. You may need to use a cake scraper to transfer them and reshape the cookies as needed.
Re-roll the excess dough and repeat. When all of the dough has been used up, bake the cookies in the oven for 10-15 minutes, depending on the size of your cookies. The edges of the cookies should be slightly golden brown.
Allow the cookies to cool completely on the baking tray.
To make the icing, combine the powdered sugar and water until it forms a thick paste.
Scoop a few tablespoons of the icing and add it to a small bowl with the matcha powder. Mix until combined.
Scoop the majority of the remaining icing into another bowl. Mix the beetroot powder into the frosting.
Use a piping bag with a small round tip to pipe the green, pink and white icing onto the cooled cookies as desired.
Mix the remaining icing with cocoa or charcoal powder and carefully 'dot' the cookies with this icing.
Allow the cookie icing to dry out at room temperature uncovered or in an loose container.
The cookies can be stored in an airtight container at room temperature for up to 3 days or in the fridge for up to a week.