Step 1

In a large mixing bowl, cream butter and sugar together using a hand mixer (or stand mixer) on medium speed until light and fluffy, about 2 minutes. Add egg and vanilla and beat until combined. Turn the mixer to low speed and add baking powder and salt. Gradually add flour and mix until combined.

Step 2

Form the dough into a ball and wrap it tightly in plastic cling wrap. Freeze for 30 minutes or refrigerate until firm (at least 1 hour, up to overnight).

Step 3

Preheat the oven to 350 F. Line a half sheet baking pan with parchment paper or silicone baking mat.

Step 4

Remove the dough from refrigerator and let it sit at room temperature for 5-10 minutes. On a lightly floured surface, use a rolling pin to roll the dough out until it is 1/4-inch thick. Use Christmas cookie cutters to cut out cookie shapes.

Step 5

Transfer the cookies onto the lined baking sheet, placing them 1-inch apart. Re-roll any scraps and repeat to cut out more cookies.

Step 6

Bake cookies for 8-10 minutes, until the edges start to turn golden brown. Let the cookies cook for a couple minutes on the baking sheet, then transfer them to a wire cooling rack to cool completely (preferably overnight, if icing).

Step 7

In medium mixing bowl, combine confectioners' sugar with meringue powder.  Add water and vanilla extract and beat with a hand mixer on medium-high speed, until smooth. If you find that the icing is too thick, add a little water (a teaspoon at a time). If you find the icing too thin, add a little more sugar.

Step 8

To colour the icing, add gel food colouring. You can also use liquid food colouring, but this will have a slight effect on the consistency of the icing. You may need to add a little more sugar to get the consistency right.