Prepare the dough the day before baking. Whisk the eggs and milk together in a jug and put the flour, yeast, sugar, spices, orange zest, fruit and a pinch of salt in the bowl of a stand mixer fitted with a dough hook. With the mixer running on medium speed, slowly pour in the egg mixture, until everything is incorporated into a soft dough. Add the butter and gradually increase the speed, kneading for 8-10 mins until the dough comes away from the sides of the bowl and clings to the hook. Scrape the dough off the hook, cover and chill overnight to prove.
Tip the dough onto a floured work surface. Briefly knead, then roll into a long sausage shape. Quarter, then divide each quarter into three pieces so you have 12 portions. Roll each into a ball and place on a lined baking tray, leaving some room between each ball for rising. Cover with a damp tea towel and leave in a warm place to prove for 2 hrs, or until almost doubled in size.
Heat the oven to 200C/180C fan/gas 6. To make the topping, mix the flour with the sugar, cardamom and about 3 tbsp water, adding the water 1 tbsp at a time until you have a thick paste. Spoon into a piping bag fitted with a small nozzle. Pipe a line along each row of buns, then repeat in the other direction to create crosses. Bake for 20 mins until golden brown. Meanwhile, heat the apricot jam in a small pan or the microwave to loosen, then brush over the warm buns. Leave to cool before serving.