Place the orange juice in a small saucepan, bring to the boil and simmer for about 3 or 4 minutes to reduce by about half. Add the sultanas and set to one side.
Warm the buttermilk for one minute on high power in the microwave. Stir in the grated apple and honey.
Stand mixer: Place flour, yeast, bicarbonate of soda, mixed spice and salt into the bowl. Briefly mix with the dough hook.
Add buttermilk mixture and sultanas in orange juice.
Mix until a smooth elastic dough forms - 5 to 10 minutes on Speed 2 of stand mixer.
Check your dough using the window pane test.
Hand kneading: Alternatively, place flour, yeast, bicarbonate of soda, mixed spice and salt in a large bowl.
Add buttermilk mixture and sultanas in orange juice and mix into a rough dough.
Dust a work surface with flour and knead by hand for 10 minutes until you have a smooth and elastic dough.
Place the dough in a large greased mixing bowl, cover and leave in a warm place to rise for 1 ½ hours until doubled in size.
Transfer the dough to a floured work surface and divide into 16 pieces, approx 75 to 80 g each. Shape into balls and place on a baking tray fairly close together and flatten each ball a little.
Cover with greased cling film or a clean tea towel and prove for one hour in a warm place.
While your Hot Cross Buns are proving, make your hot cross mix. Sift the flour into a jug, add the water and mix well until you have a smooth paste.
Preheat your oven to 400°F / 200°C / 180°C / Gas Mark 6
When your hot cross buns are ready for the oven, pipe or use a spoon to form the crosses on your buns.
Place in the oven for 25 to 30 minutes until golden brown.
Brush with honey or maple syrup for a shiny glaze and leave to cool on a wire rack.