In your blender place the sugar and orange zest and blend on turbo for 20 seconds.
Warm the milk in the microwave or pan just until it gets to 37 degrees or body temperature, just warm not too hot to touch. Then stir in the butter and the yeast and keep stiring until the butter has melted.
Now add the milk mixture to your blender with the sugar and zest in it, and mix together until combined.
Add the flour and the beaten egg, and mix for a few minutes with the dough hook if you have one, or just blend until a nice smooth dough is formed. Now you must knead the dough, so either keep in the mixer and blend for 5 mins or knead by hand. It is a very sticky wet dough so I find its easier in the mixer.
Remove from the mixer and place into a glass bowl and cover with cling film (make sure it is NOT touching the dough and there is plenty of space for the dough to rise to more than double its size. Leave to rest in a warm place on your kitchen counter for 5 hours or until it has doubled in size.
Uncover the dough and mix in the chopped Apple, Cinnamon, Chopped Orange Peel, and Chopped walnuts.
Divide the dough now into 75g portions and form nice round dough balls (check out my video on shaping bread rolls to see the method). Place on a large baking tray lined with greaseproof paper. Cover lightly with a damp tea towel and leave to rise for another hour or more.
Preheat the oven to 200C (Fan oven) 220C (static oven). Prepare the paste for making the cross, mix the 75g of white flour with 5 tablespoons of water. Place this paste into a piping bag (or freezer bag works too!). And pipe on the crosses onto each bun.
Bake for 20 minutes in the middle of the oven. Heat the apricot jam in the microwave. Remove the buns fro the oven and brush on the apricot jam while still warm. Leave to cool and enjoy !