- In a large bowl, mix together the softened butter and caster sugar until smooth.
- Mix in the flour until fully combined.
- Bring the mixture together with your hands and press it down into a shallow baking tin.
- Using a fork, gently make indentations in the shortbread.
- Air fry at 160°C for 15 minutes or until very lightly browned.
- Sprinkle with granulated sugar as soon as you take it out of the air fryer. Score lines in the soft shortbread.
- Leave to cool completely before removing from the tray.