Method

• 1.
  To make nettle butter, heat 1 tbs oil in a frypan over medium heat. Wearing rubber gloves to avoid sting, add nettles and cook, stirring, for 3 minutes or until wilted. Set aside to cool.
• 2.
  Transfer to a food processor with the butter. Season and whiz until smooth.
• 3.
  Heat remaining 1 tbs oil in a saucepan over medium heat. Cook eschalots, stirring, for 1 minute or until softened.
• 4.
  Increase heat to high. Add mussels and vermouth, and cover with the lid.
• 5.
  Cook, shaking pan occasionally, for 2-3 minutes until all mussels have opened. Remove mussels with a slotted spoon. Set aside and keep warm. Return cooking liquid to the boil. Add olives, then gradually whisk in nettle butter to emulsify.
• 6.
  Once butter is combined, return mussels to the pan, stirring to coat mussels in the butter sauce.
• 7.
  Divide among serving dishes and garnish with parsley and watercress. Serve immediately.