Add all the roll ingredients to a stand mixer with the dough hook or a large bowl. Mix until combined. Knead for about 3-5 minutes or until the dough comes away from the sides of the bowl and forms a soft dough. If the dough is too wet, add a little more flour and knead until it's no longer sticky (avoid doing this if you can as it'll make the rolls drier). If the dough is too dry, add a dash of milk and knead until it forms a smooth dough.
Cover the bowl with a damp tea towel. Set it aside in a warm spot for 1 hour or until the dough has increased or doubled in size.
To prepare the filling: Combine the sugar and cinnamon in a small bowl.
Dust a clean surface with flour. Scoop the dough onto the surface and roll it out into a large rectangular shape.
Use a pastry brush to spread the melted butter or margarine on the dough, making sure it reaches all edges. Liberally sprinkle the cinnamon sugar and rub it into the surface with your fingertips.
If your dough is too soft to be rolled, chill it in the fridge for at least 10 minutes. Starting from the long side, tightly roll the dough into a large tube. Use a sharp knife to cut rolls out of the dough.
Place the rolls on a baking tray, leaving a little space between each roll to allow them to spread. Cover the tray with a damp tea towel and allow them to rise for at least 1 hour. You can do this step overnight if you leave the rolls in the fridge.
When you're ready to bake the rolls, preheat the oven to 180°C (350°F).
When the oven is hot, bake the rolls for 15-20 minutes. The rolls are ready when they are slightly golden brown or when you insert a skewer in one of the middle rolls and it doesn't have wet dough on it. Set aside to cool.
To make the frosting: Whisk all of the ingredients in a small until smooth and there are no lumps. Generously drizzle the frosting onto the rolls.
The rolls are best eaten the day they are baked. Alternatively, store them in an airtight container at room temperature for 1-2 days or in the fridge for 3-4 days. Warm up the rolls before you enjoy them.