Make the brioche dough the day before serving. For the dough, put the flour, sugar, yeast, salt and spices into the mixing bowl of a stand mixer with the dough hook fitted.
Add the eggs and knead on a low speed for five minutes.
Scrape down the sides of the bowl, then knead at medium speed for 10 minutes. The dough will be smooth, elastic and well amalgamated.
Start adding the butter to the dough a few pieces at a time, whilst mixing at low speed. When all the butter has been added, work the dough at a higher speed for 6-10 minutes until dough is smooth, shiny and elastic and comes away from the sides of the bowl.
Cover the dough and leave in a cool place overnight (10-12C/50-54F is best).
Soak the sultanas in the orange flower water, for the filling, and leave overnight also.
The next day, allow the dough to come back up to room temperature and finish proving.
Roll out the dough into a square and scatter over the soaked sultanas, pistachios, orange zest and marzipan.
Divide the dough into approximately 90g/3¼oz pieces and form into balls.
Generously butter a 28cm/11in pie tin and four small brioche moulds.
Place 11 balls in a circle in the pie dish, just slightly apart.
Form the remaining dough into four brioche à tête by pressing with the edge of your hand into the ball two-thirds of the way across and ‘sawing’ the dough to make a small head. Lift the head to stretch it from the ‘body’, then press the head into the body. Place the shaped brioche into the buttered moulds.
Cover the dough and leave to prove for up to 2½ hours.
Preheat the oven to 190C/375F/Gas 5.
Brush the brioche with egg wash and bake the buns and wreath for 10 minutes at 190C/375F/Gas 5. Reduce the oven temperature to 180C/350F/Gas 4 and continue to bake the small brioche for five minutes more, until dark golden-brown, then remove from the oven. When the small brioche come out of the oven, cover the wreath with aluminium foil and continue to bake for 15-20 minutes more. Remove from the oven when dark golden-brown.
Remove the brioche from the tins and cool on a wire rack.
For the orange curd, heat the juices, zest, salt, sugar, butter and eggs in a heavy saucepan, or in a bain marie, over a low heat. Stir the mixture constantly until it thickens and coats the back of a spoon.
Sieve the orange curd and add the orange liqueur and leave in the fridge to firm up.
When the orange curd has cooled, cut a cone out of the brioche à tête and place a small amount of curd into each brioche. Return the brioche tops and dust with icing sugar.
Mix the orange juice with the icing sugar to make icing. Drizzle the orange icing over the wreath in a random pattern and sprinkle with the toasted flaked almonds, pistachios and decorate with edible gold stars and green and red icing decorations.
Mix the orange juice with the icing sugar to make icing. Drizzle the orange icing over the wreath in a random pattern and sprinkle with the toasted flaked almonds, pistachios and decorate with edible gold stars and green and red icing decorations.