Line large baking sheets with parchment paper or silicone baking mat

Preheat oven to 350 degrees

Cream butter and sugar together in a stand mixer (or in a large bowl with a hand held mixer) until fully combined and light in colour

With the mixer off, add in cocoa powder and mix in on low, scraping down the sides as needed

Add in the egg and vanilla and mix until completely combined, scraping sides with spatula again as needed to evenly combine

With the mixer turned off add in the flour and baking powder, mix on low until combined

Work dough a few times with clean hands to ensure everything is combined and has a workable texture, either in the bowl or on a lightly floured surface (keeping in mind too much flour will muddy the chocolate surface colour if not worked into the dough)

Roll out onto silpat or parchment to 1/8 - 1/4" thickness

Use Cookie cutters to cute out shapes on the cookie sheets and leave all surrounding dough in place (this will help have less distortion when baking, you could also chill the dough on the pans for 30 minutes at this stage)

Bake in the 350 degree oven for 10 -12 minutes (when they are done they lose a little of their shine and smell intensely chocolatey)

Remove from oven and immediately use the cookie cutters to recut the shapes, trying to follow the original lines as exactly as possible.

Allow to cool 2 -5 minutes on the pan and then carefully separate and remove to a cooling tray to cool, using a small knife or spreader to separate any finicky edges or pieces.

Once completely cooled, assemble with royal icing