To make the dough, combine the flour, corn flour, caster sugar and salt in a separate bowl and mix together.
Pour the milk into the bowl of a stand mixer. Add the yeast and sugar, and stir gently to combine. Set aside until foamy (about 10 minutes). Add the beaten egg and dry ingredients on top of the milk mixture. Using the dough hook attachment, knead on low speed for about 2 minutes.
Add the butter gradually and keep kneading on medium speed until the dough is smooth and elastic, this will takeabout6-8 minutes. If kneading by hand, knead for about 8-10 minutes.
Transfer the dough to a lightly oiled bowl, cover it and stand in a warm place until doubled in size (1-1.5 hours).
To make the filling,cream the butter and sugar until light and fluffy. Stir in the Apple Cake Spice and salt flakes.
Grease a deep baking dish and line the base and sides with compostable baking paper.
Turn the dough out onto a lightly floured surface and roll it out into a 30 x 50cm rectangle, making sure the long side is facing you. Spread the filling evenly over the top and sprinkle with walnuts and grated apple. Roll up the dough starting at the bottom and finishing with the seam down.
Cut the log into 12 even slices using a sharp knife. Place the slices into the prepared baking dish, cut side up, spacing them out evenly. Cover with a clean tea towel. Leave in a warm place to prove for about 30 minutes.
Preheat oven to 180°C.
Once the scrolls have proved, bake them for 15-20 minutes, until golden brown.
To make the glaze, sift the icing sugar into a medium bowl, then add the milk. Drizzle it over the baked scrolls once they have slightly cooled down. Sprinkle with rose petals, if desired.
The scrolls can be served warm or at room temperature and are best enjoyed on the day of baking.