Make the batter first by mixing all ingredients together, transfer to a bowl and cover down with some cling film and leave to rise for approx 30 minute until the mixture has bubbled up.
Meanwhile sieve the flour, salt, cinnamon and nutmeg together.
Add in the orange zest and butter and rub the small amount of butter into the dry ingredients. Sugar ad dried fruit can be incorporated at this stage also.
Pour the batter in on top of the dry ingredients and add in the two egg yolks for added richness. Mix until all of the ingredients have come together.
Transfer the mixture onto a floured work surface and kneed for 4-5 minutes until the mixture has come together.
Divide the dough into 9 balls and place them side by side on a flat baking sheet (A little room between each as they will spread) and cover them with a dry cloth. Leave to rise for approximately an hour in a warm environment.
When the rolls have risen dramatically take a sharp knife and place a cross on top of each one of them
(Alternatively you could blend some flour with some water and pipe a cross on top of the either)
Bake in the oven at 190°C (375°F/Gas 5) for 20 minutes until golden brown.
To make the Orange & Cardamom Glaze:
Bring all ingredients to the boil for 3-4 minutes until a thick syrup has been achieved.
Brush the top of the buns with this boiling syrup. Serve.