Gratin of Mussels with Spinach

• 50 mussels, i.e. 4–5 pints (2.3–2.8 litres) depending on size
• 1¼

Clean the mussels, and steam them open in a lidded pan with one cup of water, for 2 or 3 minutes. Save the resulting juice and remove the mussels from their shells. Discard the shells.

Wash the spinach and shake it fairly dry. Pop into a saucepan over a low heat. Do not add any water but cook gently just in the water that has been retained on the leaves after washing, until you can mash