Preheat oven to 180C. In a large bowl, mix together the plain flour, spelt flour, baking powder, sugar, salt and cinnamon.
Add the cold butter cubes and gently rub together until you are left with pea-sized pieces of butter.
Stir in the blood orange zest and the chocolate chunks.
Add the lightly beaten egg (reserve a drop for brushing the tops) and the milk and bring together gently using your hands to form a dough, adding more milk if needed. You don't want the dough to be dry but you don't want it to be super sticky either. Pat the dough into a round, 1" thick.
Cut into 8 wedges. Brush with the reserved beaten egg.
Place on a lined baking tray and bake for 12-15 minutes until risen and golden brown. Leave to cool a little before drizzling with glaze and serving.