Add flour to a large bowl and add the yeast, raisins, mixed spice and 350ml water. Mix into a soft dough, cover with a tea towel and leave aside for 3 hours at room temperature to rise. The dough will expand and become smoother in appearance. If you want to leave it overnight, just leave in the fridge.
Heat oven to 160°C /gas 6. Grease a 12-hole muffin tin with butter. Divide the dough into 12 and roll each portion into a neat ball on a floured work surface and place one into each hole in the tin before baking for 20 minutes.
Roll out the marzipan and cut into 1cm wide strips to make the crosses for the buns. Combine the sugar with 2 tbsp water and leave to dissolve. When the buns are done, remove from the oven and lay a marzipan cross on each before placing them back in the oven for 5 minutes. Take the buns out, glaze with the sugar water and leave to cool.