Add the caster sugar and cinnamon to a small bowl and toss together, until combined. Set aside. 

Add 100g of the softened butter to a separate medium bowl. Add about half of the cinnamon sugar and mix together, until combined. 

Using a rolling pin, roll the slices of bread out lightly so that the crusty edges are flattened slightly. Divide the cinnamon sugar butter mixture over the slices of spread and spread it out over the surface. Roll the bread up into a cylinder. 

Place the rolls, seam side down, into your air fryer. Melt the remaining 50g of butter in the microwave, then brush the tops of the rolls with the melted butter. 

Air fry at 200C for about 8 minutes, until golden brown and crispy. 

Sprinkle the remaining cinnamon sugar into a small, shallow dish. Roll the warm cinnamon rolls in the cinnamon sugar, to coat. 

Add the cream cheese to a small bowl and add 2 tsp of any remaining cinnamon sugar. Mix together, until combined and smooth. Add a splash of milk if needed to thin the cream cheese. Transfer the cream cheese mixture to a snap lock bag and snip a small hole in the corner of the bag. 

Pipe the cream cheese mixture over the top of the cinnamon rolls. 

Serve them while they are still warm!