The true origin of the blanc mange is obscure, but it is believed that it was a result of the Arab introduction of rice and almonds in early medieval Europe. Several other names for related or similar dishes existed in Europe, such as the Anglo-Norman blanc desirree ("white Syrian dish"). The "white dish" (from the original Old French term blanc mangier) was an upper-class dish common to most of Europe during the Middle Ages. It occurs in countless variations from recipe collections from all over Europe and is mentioned in the prologue to Geoffrey Chaucer's Canterbury Tales.
Take Caponis 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.
Place the chicken breast in a pan and cover with water, bring it to a boil, reduce the heat, and simmer until the meat is cooked. Drain and tear it into very fine threads.
Moisten the rice flour with a little of the almond milk. Put the rest of the almond milk into a saucepan with the cream, salt, and sugar, and bring the liquid to boil over medium heat, stirring constantly. Add a few spoonfuls of the hot liquid to the moistened rice flour, and pour the mixture into the pan. Reduce heat.
Beat vigorously and continue to cook over a low heat, stirring so it doesn't stick to the bottom of the pan, until the mixture begins to thicken. Beat in the fine threads of chicken and continue to cook the mixture until thick.
Garnish with ground cinnamon and lightly-toasted almonds. Refrigerate any leftovers.