Knead all the ingredients for the dough for about 5–10 minutes (using a kitchen machine) until a smooth dough forms.
Cover the dough and let it rise for about 1 hour at room temperature or 8–12 hours in the fridge. (If you are proofing the dough overnight, allow it to "acclimatize" at room temperature for at least 30 minutes before continuing.)
Roll out the dough into an even rectangle, at least 5 mm thick (about a small finger thick). (See my tips above in the post.).
Mix the cinnamon with the sugar, and peel the apples before cutting them into small cubes (the smaller, the better).
Brush the pastry with oil (or soft vegan butter) and sprinkle it with the sugar-cinnamon mixture and the diced apples. Leave about 2 cm (1 inch) free at the top long side.
Roll up the dough tightly, starting from the bottom and rolling towards the top long side.
Cut the roll into slices about 2 to 3 cm (1 inch) wide to create the rolls. Depending on the size of the rectangle and the slices, you will get approximately 12 pieces.
Place the apple and cinnamon rolls on a baking tray lined with parchment paper or in a greased baking tin. Cover them with a tea towel and let them rise for another 30 minutes at room temperature.
Meanwhile, preheat the oven to 180°C (360°F) using top and bottom heat.
Bake the rolls on the middle rack for about 20–25 minutes, or until they start to brown.
Switch off the oven and open the door. If desired, brush the rolls with a little melted vegan butter. (To melt the butter, place a small piece on a plate or bowl and briefly leave it in the warm oven.) Allow the rolls to cool slightly.
While the rolls cool, prepare the icing. Mix the powdered sugar with the lemon juice until smooth, and drizzle it over the rolls using a spoon. Let the icing set briefly before serving.