In a small bowl, soak the currants in the brandy for 10 minutes.
In a medium-sized bowl, whisk together the flour, cocoa powder, baking powder, baking soda, spices, salt, and dark chocolate.
Beat the butter, sugar, vanilla, and lemon and orange zest to combine, but don't aerate much (~ 1 minute)
While the mixer or beater running, slowly add the egg and mix for about 1 minute.
Add the dry ingredients, followed by the currants and brandy. Mix until everything comes together.
Gently knead the dough in the bowl with your hands until it's uniform.
Divide the dough into 1 ¾ oz chunks and roll each chunk into a perfectly round ball.
Place the balls on 1 or 2 baking sheets lined with parchment paper, spacing them about ¾" apart, and let rest in the fridge for at least 1 hour.
Preheat the oven to 375° F. Bake the cookies for 15 minutes, until the top firms up but the center is still soft.
Remove from the oven.
Once the cookies are out of the oven, allow to cool for only 5 minutes, and then transfer to a wire rack.
While the cookies are still warm, whisk together the glaze ingredients until a thin and smooth icing forms.
Pour a tablespoon of the glaze over each cookie, leaving it to drip and coat the cookie with a very thin, almost transparent film. (You may want to repeat this step for a thicker glaze)
Top each cookie with 3 pieces of candied peel placed at the center.
Leave to set and then serve, or store in an airtight container for a day or two