Add the butter and sugar to a mixing bowl and beat until smooth and creamy.

Add the egg, vanilla extract, and almond extract and beat until combined.

In a separate bowl, whisk together the flour, baking powder, cornstarch, and salt.

Add the dry ingredients to the wet ingredients and stir together until combined into a smooth dough.

Shape the dough into a ball with your hands, cover in plastic wrap, and place in the fridge to chill for 1 hour.

Preheat the oven to 350F and line two baking sheets with parchment paper. Roll out the dough to approx. ¼” thickness and cut out shapes using Christmas-themed cookie cutters of your choice.

Place the cookie shapes on the prepared baking sheets and bake for 10 minutes or until just starting to go golden around the edges.

Leave on the baking sheets for about 10 minutes, then transfer to a wire rack to cool completely.

Using a piping bag and narrow nozzle, pipe lines around the edge of each cookie.

Using a wider nozzle, flood the middle of the lines to fill them in. If you need to make the icing a little runnier, add a few more drops of milk.

If adding a second layer of icing, allow the cookies to dry for at least 30 minutes first.

Leave the cookies to dry in the open air at room temperature for at least 6 hours or preferably overnight before touching or stacking.