Rub the orange zest with the sugars until fragrant.
Beat the butter into the sugars and mix until light and fluffy.
Mix in the egg and vanilla.
Whisk the gluten-free flour, almond flour, mixed spice and salt together in a large mixing bowl.
Pour the flour mixture into the rest of the cookie batter and mix until combined.
Finally stir in the marzipan, currants and half (50g) of the chocolate.
Cover the bowl and chill in the fridge for 1 hour.
Tear off some of the cookie dough, weigh to 40g then roll into an even ball between the palms of your hands. Repeat with the rest of the dough then arrange the dough balls across two baking trays with plenty of space in between.
Place the baking tray in the fridge for about 15 minutes.
Pre-heat the oven to 190°C / 170°C fan assisted /gas mark 5 / 375°F.
Bake the cookies in the centre of the oven for 12-14 minutes until turning golden at the edges.
Allow the cookies to rest on the baking tray for 10 minutes.
Melt the remaining chocolate in the microwave or in a bowl set over a pan of simmering water, whilst the cookies are cooling.
Move the cookies to a wire rack and drizzle with the melted chocolate.