Use a whisk to beat the butter, sugar and salt together until you have a creamy consistency.
Add the egg and mix it in until fully incorporated.
Add the vanilla and spices and mix once again.
Add the flour and baking powder and mix using a spatula. Once the spatula isn't helping anymore, knead slightly with your hands.
Cover the dough and place in the fridge for 30 minutes.
If your dough has been in the fridge for more than 30 minutes, it's possible that you will have to wait a few minutes for it to come back to room temperature before rolling it out to prevent it from breaking. Roll out the dough on a floured surface until it's 2-3mm thick.
Use cookie cutters to cut the cookies. I cut 3 cookies per size which measure from point to point: 13, 11, 9, 7, 5 and 4cm. You get to cut a bit more than this so I made a few extra small ones: one for the tip and the rest for eating ;).
Use a thin metal spatula to lift out the cookies from the surface.
Place the cookies on a non-stick baking tray. If your tray is not non-stick, line it with baking paper or silpat first.
Bake the cookies in a preheated oven at 180°C / 350°F for 8-12 minutes or until slightly golden.
Let them cool down completely before decorating or the royal icing will melt.