Blancmange is one of the easiest period dishes to make and is an excellent dish for someone who wants to add a touch of traditionalism to the holiday meal. For those more creative, try making a layered dessert by refrigerating layers of colored gelatin and blancmange in the mold and perhaps garnishing with fresh fruit.
Middle Ages blancmange usually included pounded capon or chicken breast and sweetened almond milk, but by the 1700’s the chicken was forgotten.
Receipts from the 18th century have the cook to discard the almond solids after the “milk” has been strained. Blancmange is basically a thickened gelatin made with milk. The French term was blanc mangier. It got its white color from the milk used in it unless it was colored with some substance such as spinach juice, cochineal, or saffron.
Blank Maunger. XXXVI. Take Capouns and seeþ hem, þenne take hem up. take Almandes blaunched. grynd hem and alay hem up with the same broth. cast the mylk in a pot. waisshe rys and do þerto and lat it seeþ. þanne take brawn of Capouns teere it small and do þerto. take white grece sugur and salt and cast þerinne. lat it seeþ. þenne messe it forth and florissh it with aneys in confyt rede oþer whyt. and with Almaundes fryed in oyle. and serue it forth. – The Forme of Cury, 1390. England.
[The cook was to boil a capon, grind the meat in a mortar and put it into a pot. Rice was to be cooked with it along with white grease, sugar, and salt.]
The following receipts for blancmange will show the various substances used over the course of several decades to thicken the mixture and then we’ll conclude with a strictly modern version anyone can make.
In 1844, Lady Charlotte Campbell Bury’s receipt book offered the cook the choice of using hartshorn [initially ground horn of a male deer, or hart, later ammonium carbonate also called baker’s ammonia] or isinglass. Ms. Parloa’s receipts for blanc-mange include a version thickened with Irish moss instead of gelatin which she said was the best sort. Blancmange was still being thickened with Irish or Carragheen moss into the 1890’s. – Bury, Charlotte, Lady. The Lady’s Own Cookery Book. London.
Into the last quarter of the 19th century blancmange was still thickened with ground rice flour and with arrow-root or cornstarch as well as some of the thickeners already discussed.
I tried to purchase some Carragheen moss the last time I was in Scotland, but the store had none in stock. I was there for an extended period of time, but time moves slowly there, and they still had not placed an order to replenish their stock when I left to return home.
Richard Briggs’ book  contains versions thickened with calves foot jelly and with isinglass, as does John Mollard’s in 1802.
BLANCMANGE. Mollard, John. The Art of Cookery Made Easy and Refined. 1802. London. Put a pint of warm cleared calves foot jelly into a stewpan; mix with it the yolks of six eggs, set it over a fire, and whisk it till it begins to boil. Then set the pan in cold water and stir the mixture till nearly cold, to prevent it from curdling, and when it begins to thicken fill the shapes. When it is ready to be served up dip the shapes in warm water.
AMERICAN BLANCMANGE. The Ladies’ New Book of Cookery. Sarah J. Hale. 1852. NY. Mix 2 oz. of arrow-root in half a pint of cold water; let it settle for a quarter of an hour; pour off the water and add a table-spoonful of orange or rose water; sweeten 1 quart of new milk; boil it with a bit of cinnamon, half the peel of a lemon, and 4 laurel or bay leaves; pour the boiling milk upon the arrow-root, stirring it all the time: put it into the mould and turn it out the following day.
BLANCMANGE. Bishop, Frederick. The Wife’s Own Book. 1856. London. Take one ounce of picked isinglass, boil it in a pint of water with a bit of cinnamon till it is melted, add three quarters of a pint of cream, two ounces of sweet almonds, six bitter ones blanched and beaten, a bit of lemon peel; sweeten it and stir it over the fire. When it boils, strain it and let it cool, squeeze in the juice of a lemon, and put into moulds. It may be garnished according to fancy.
Irish Moss or Carrigan BLANCMANGE. Peterson, Hannah Mary Bouvier. 1870. Philadelphia. Soak half an ounce of the moss in cold water for a few minutes; then withdraw it, shaking the water from each sprig, and boil it in a quart of milk till it attains the consistency of jelly, and sweeten to the taste.
BLANC-MANGE WITH GELATINE. Parloa, Maria. The Appledore Cook Book. 1880. Boston. Soak a box of gelatin in cold water enough to cover it one hour. Put three pints of milk in a tin pail, and set in a kettle with hot water; when the milk comes to a boil, stir in the gelatin and two spoonfuls of sugar. Flavor with vanilla or lemon, strain into blanc-mange moulds, and when cool, set on ice to harden. Make this, if possible the day before it is to be used. Serve with sugar and cream.
Corn-starch Blancmange. Allen, Horace. 1883. Philadelphia. One quart of milk, four tablespoonfuls corn-starch, wet in a little cold water; three eggs, well beaten, whites and yolks separately; one cup of sugar, vanilla or other essence, and one saltspoonful salt.
1st. Heat the milk to boiling. 2nd. Stir in the cornstarch and salt, and boil together five minutes. 3d Add the yolks, beaten light, with the sugar, and boil two minutes longer, stirring all the while. 4th. Remove the mixture from the fire, and beat in the whipped whites while it is boiling hot. 5th. Pour into a mould wet with cold water, and set in a cold place. 6th. Eat with sugar and cream.
BLANC-MANGE, Gesine Lemcke. Desserts and Salads. 1911. NY. Boil 1 quart milk with 6 Tablespoonfuls sugar; add 1 ounce gelatin which has been soaked in a little cold water for 15 minutes; stir this over the fire until gelatin is dissolved; rinse out a form with cold water, sprinkle with sugar, pour in the blanc-mange and set it on ice; swerve with vanilla sauce.
BLANCMANGE, modern version. 1 pint of milk, 1 pint of heavy cream, 4 oz. caster sugar, 1 ¼ oz. of unflavored gelatin, ½ oz. sweet almonds, blanched, and crushed into a paste, the zest of 1 lemon, ¼ tsp. almond extract. Put the milk into a pan with the gelatin and lemon zest. Add the almonds and almond extract. Allow the mixture to come to a boil, stirring so it doesn’t scorch. As soon as it boils, strain the mixture. To the liquid milk mixture, stir in the cream and stir until it cools. (Placing the pan into a sink with ice cubes speeds the process). Let the mixture stand for a few minutes while you prepare a mold. Very lightly coat the mold with vegetable oil or spray with cooking spray. Pour the mixture into the mold, and refrigerate until firm.
SOURCES: Isinglass: Available from amazon.com in powder form. Irish moss: Amazon.com. Unflavored gelatin: Knox gelatin is available from grocery stores. It can be purchased in bulk through Amazon.com.