In a small bowl combine yeast, sugar, and milk. Gently stir to combine, and let rest for 10 minutes to activate the yeast.
In a bowl of a stand mixer, fitted with a dough hook combine all-purpose flour, strong bread flour, a pinch of salt, yeast mixture and an egg. Knead for about 5 minutes, then gradually incorporate softened butter. Once all the butter has been incorporated, continue to knead the dough for about 5 minutes. Cover with cling film and set aside for 10 minutes.TipDouble the time of kneading if you are kneading by hand.
Add the raisins, candied orange, spices and rum (optional) to the dough. Knead for about 5 - 10 minutes or until the dough is elastic and glossy. Cover with cling film and let rise for about 50 minutes at room temperature, or until doubled in size.
divide the dough
Divide the dough into 15 equal parts, each weighting around 60 grams / 2 ounces. Shape each piece of dough into a round ball.
Place each ball on a baking sheet lined with parchment paper. Don't overcrowd them because they will rise and spread. Cover and let rise at room temperature or until doubled in size, for about 50 minutes.
To make the crosses: Combine water, flour, melted butter and salt together in a small bowl until you get a thick, fine paste. Keep chilled in the refrigerator until needed.
To make the glaze: Add water, sugar, orange, lemon, and spices to a saucepan and bring to a boil. Take off the heat and set aside to cool.
Preheat the oven to 180°C / 350°F. Fill a piping bag with the crosses mixture. Pipe lines across tops of the buns in both directions, to form a cross. Place the buns in the preheated oven and bake until golden brown, for about 25 - 30 minutes.
Remove from the oven. Brush lightly with sweet glaze and allow to cool on a wire rack or serve them still warm with a generous amount of butter. Enjoy.