• Cut a piece of greaseproof to about the same size as the base of your tray. Fold it in half 3-4 times to create a thin triangle. Make holes with a skewer or hole punch and unfold.

Make the dough

• Put the butter, sugar, eggs and vanilla in a mixing bowl. Whisk until fluffy and pale.
• Sift in the flour, baking powder, salt and bicarbonate of soda. Stir until fully combined and clumpy.
• Gather up the pieces and knead together only as much as it takes to get a smooth ball of dough.
• Roll the dough into a rough cylinder with a length of 25cm and a diameter of 4cm.
• Wrap in greaseproof paper or plastic wrap, smoothing the dough into an even cylinder.
• Place in the fridge to rest and chill for 15 minutes. Bonus tip! If your dough has warmed, it may tend towards flattening against the counter. To avoid this, you can use a couple of kitchen roll tubes and a little tape to hold the cylinder in shape.

Shape and bake the cookies

• Slice the cylinder into 1cm discs with a sharp knife. You should get 25 cookies in total.
• Place 6-8 cookies in your lined air fryer basket. They don't need to be spaced more than a centimetre or two (half inch) apart as they only spread a little bit.
• Set the air fryer to 170C and bake the cookies for 8 minutes or until pale golden at the edges.
• Cool briefly on the tray to allow them to firm up, then transfer to a cooling rack with a spatula.