Combine yeast, sugar, warmed milk and ⅓ cup (80ml) warm water in a bowl. Set aside for 5 minutes or until mixture is foamy. Add egg and whisk to combine.
Combine flour with McCormick Allspice and Ginger in a bowl. Use your fingertips to rub butter into flour mixture until it resembles fine breadcrumbs. Stir in the currants then make a well in the centre. Pour the yeast mixture into the well and stir until a dough forms. Turn onto a lightly floured surface, knead for 10 minutes or until smooth and elastic.
Place dough in a lightly greased bowl. Cover with plastic wrap and set aside for 1 hour or until dough doubles in size.
Preheat oven to 200°C. Grease a 20cm x 30cm slice tin. Turn dough onto a lightly floured surface and knead until it returns to original size. Divide into 12 portions and roll into balls. Place side by side in pan. Set aside in a draught-free place for 30 minutes or until doubled in size.
To make flour paste, combine flour, sugar and ¼ cup (60ml) cold water in a bowl. Spoon into a snap-lock bag and snip off 1 corner. Pipe crosses onto buns. Bake for 10 minutes. Reduce oven to 180°C and bake for 20 minutes or until golden.
Meanwhile to make glaze, combine gelatine, sugar and 1 tbsp boiling water in a bowl, stirring until sugar and gelatine dissolve. Turn buns onto a wire rack. Brush buns with glaze. Serve with butter.