Orange Sponge Pudding

 "Separate 3 eggs and bet whites stiff. To yolks, add the juice and grated rind of one orange and the juice of 1/2 a lemon. Combine 1and1/2 cups sugar  with 3 Tablespoons flour, and work in 4 Tablespoons butter and add 1/2 cup milk. When this is smooth, beat  it into egg yolks. Fold in beaten whites. Bake for 45 minutes in a moderate oven. "