Method

1. Preheat the oven 200°C and grease and line a deep, square baking tray.  
2. In a small bowl combine the warm milk, yeast and sugar. Allow to stand for 5-10 minutes and the mixture is frothy.  
3. In a large bowl sift together the flour and mixed spice and stir through the orange zest (optional). Make a well in the centre and add the melted butter, egg and yeast mixture from step 2. Mix together until a loose dough forms. The dough should be soft and slightly damp. If it feels a little dry then add extra warm water, a tablespoon at a time. Turn out the dough onto a floured surface and knead until it is smooth and elastic. Knead in the sultanas.  
4. Form the dough into a ball and place in a lightly oiled bowl. Cover with a tea towel and leave to stand in a warm place for 30 minutes and the dough has doubled in size. Knock down the dough and divide it evenly into 18 smooth balls. Place the balls onto the baking tray in three rows of six. Cover the tray with a damp tea towel and leave to stand in a warm place for 20 minutes. (If you don’t have a deep, square baking tray try placing the balls on a flat baking tray spaced 2 cm apart, cover with a tea towel and allow to rise and expand, for 20-40 minutes, so the balls are touching.)  
5. While the buns are rising make the cross paste by combining the flour and water to form a smooth, thick paste. Pipe a cross through the centre of each bun using a piping bag (alternatively use a snap lock bag with a corner trimmed). Bake for 15-20 minutes or until golden and cooked through 
6. For the glaze place the sugar, mixed spice and water in a small pan, bring to the boil and boil for 2 minutes, then brush over the hot buns. Transfer to a wire rack to cool slightly. Serve warm or toasted with butter.