Pancakes with spinach and cheese

• 12 pancakes

Tear away coarse midribs and thoroughly wash spinach in cold water. Pack wet spinach into a saucepan, cover with a pan lid and cook over moderate heat for 10 minutes until spinach is tender. (The water clinging to the leaves will provide sufficient cooking liquid.) Drain well by pressing the spinach in a colander, then finely chop or pass through a food mill.

Melt the butter in a saucep