If you open freeze pre-prepared choux buns on trays lined with baking paper, you can cook them in the air fryer from frozen (or bag them up until you're ready to bake). For the pastry, melt 1.75oz (50g) butter, add 5fl oz (150ml) water and a pinch of sea salt, then bring to the boil. Take off the heat, add 2.5oz (75g) plain flour, all in one go, and stir until it forms a thick lump that leaves the sides of the pan. Put into a bowl to cool, then add two beaten eggs using an electric hand whisk. Spoon walnut-sized blobs onto baking paper and freeze. When ready to bake, heat the air fryer to 180ºC (350ºF), cook for 10 minutes, then cool on a wire rack. Split and fill with whipped cream, then drizzle with melted chocolate to serve.