Preheat oven to 200c/395f.
Line a 12 hole muffin tin (mine is ½ cup capacity) with paper cases.
In a large bowl, sift together self-raising flour, mixed spice, cinnamon and bicarbonate of soda. Mix to combine.
375 g self-raising flour, 1¼ teaspoon mixed spice, ½ teaspoon cinnamon, ½ teaspoon bicarbonate of soda
In another bowl mix together buttermilk, melted butter, caster sugar and eggs.
100 g salted butter, 2 eggs, 250 ml buttermilk, 180 g caster sugar
Add buttermilk mixture to flour mixture and mix until just combined - don't over mix.
Add sultanas and currants and mix lightly to combine, then divide the mixture amongst muffin papers. Bake for 15 - 20 minutes or until browned on top and a skewer comes out clean when inserted into the centre.
1 cup sultanas, ½ cup currants
Once buffins have cooled, brush a small amount of the sugar glaze on top of each buffin (if using), then pipe an icing "cross" on top of each buffin (if using).