Pare the rind of the oranges very thinly, cut into fine shreds, plunge them into boiling water and boil 5 minutes. Strain.

Prepare a brown roux by melting the butter in a small saucepan, stirring in the flour and continuing to stir over a gentle flame until the mixture is quite smooth and turns café au lait colour; now add half the warmed stock, stir again, then add the other half. Cook very gently another 5 minutes. Add the seasonings, the strained juice of one of the oranges and the peel. A few drops of Madeira or port added at the last moment are an improvement and the juices which have come from the bird while roasting should also be added.

Those who prefer a milder sauce can omit the orange juice and make up the quantity, with a little extra stock. In any case, this is not a sauce to be served if you are drinking a fine wine with your duck; it would overwhelm it. If it is to go with a domestic duck, the stock can be made from the giblets.