1 quart fresh peas
1 onion
1 large sprig mint
1 teaspoon salt
1 teaspoon sugar
4 tablespoons butter
2 egg yolks
½ cup cream

Shell the peas and break up the pods. 

Wash the pods and boil for two or three hours in the water in which other vegetables have been cooked, if possible. 

Strain and add the peas, the onion, mint, salt, and sugar, and three pints of water in which the pods were cooked. 

Cook until peas are tender, then rub through a sieve. 

Add butter and bring to boiling point.  S

eason more if needed, and just before serving add the egg yolk diluted with the cream.  Cook, stirring constantly for five minutes, but do not allow the liquid to boil.  Strain and serve with croutons.