• Melt the butter in a pan, on a very very low heat!
• Pour the butter into a mixing bowl with caster & light brown sugar and mix with a wooden spoon/spatula until fully combined. Should take about a minute.
• Crack the egg into the same bowl. Mix together until just combined. Set aside.
• Put the flour, salt and baking powder into another bowl. Stir with a spoon so that its all evenly mixed together.
• Add the flour to butter/sugar mixture & stir until fully combined. Note – It will look like a lot of flour! Keep stirring and it’ll all come together. Promise!
  
• Cover with cling film and place into the fridge for at least an hour.
• Remove from the fridge and divide into 14 balls – about golf ball sized.

  >The mixture should not be too sticky at this stage. If it is, place it back in the fridge to firm up.
• Place onto baking parchment on a baking tray, leaving lots of room around them. Put into the oven for 12-15mins at 175oC until the edges are browning but the middles are still gooey.
• Remove from the oven and carefully cut them down the middle - just off centre like my picture. Leave to cool on the baking tray for at least 10-15mins before attempting to move them – they are VERY fragile when warm but they harden up once they start to cool.
  

Construction

• Once completely cool, whisk the butter and icing together until pale and smooth. Takes approx 3-4mins.
• Place the icing into a bag & pipe like my picture on the larger half of the cookie.
  
• Sandwich the other half on top, at a slight angle so it looks like a mouth!
• Stick on some eyes with a tiny bit of butter icing - I think they look better if they're close together, like the Cookie Monster!
• Eat!!!!