Just as when we say “Italian seasoning”, there was no set list of ingredients, rather just the spirit of an idea that you attempted to capture. It may well be that various merchants selling it would have kept their ingredients and proportions secret.
It was mix you would have on hand, just as we would have curry powder and “poultry seasoning” today.
The anonymous writer of Le Menagier de Paris (1393) suggested for powder douce: cinnamon, ginger, grains of paradise, nutmeg, galingale, and sugar, all ground and mixed together.
Some other recipes suggested sugar, cinnamon, cloves, and mace.
Though the exact ingredients and exact proportions are not certain, in 1790, Samuel Pegge, in his “The Forme of Cury – A Roll of Ancient English Cookery” suggested it was ground galyngal, or ground mixed spices.
The temptation is to think that it must have always contained sugar, but then some recipes that called for it also called for sugar to be added as well. Perhaps the Powder Douce they had in mind had no sugar in it, or perhaps the recipes just wanted additional sugar.
The English sometimes got mixed up and called it “duke’s powder” instead of “douce powder.”
Here’s one interpretation:
3 tablespoons of ginger
2 tablespoons of sugar
1 1/2 tablespoons of cinnamon
1 tablespoon powdered bay leaves
1 teaspoon ground cloves
1 teaspoon nutmeg
4 parts Apple pie spice or Chinese 5 spice powder to 1 part sugar
Literature & Lore
“Powder-douce, which occurs so often, has been thought by some, who have just peeped into our Roll, to be the same as sugar, and only a different name for it; but they are plainly mistaken, as is evident from 47. 51. 164. 165. where they are mentioned together as different things. In short, I take powder-douce to be either powder of galyngal, for see Editor’s MS II. 20. 24, or a compound made of sundry aromatic spices ground or beaten small, and kept always ready at hand in some proper receptacle. It is otherwise termed good powders, 83. 130. and in Editor’s MS 17. 37. 38 . or powder simply, No. 169, 170. White powder-douce occurs No. 51, which seems to be the same as blanch-powder, 132. 193. called blaynshe powder, and bought ready prepared, in Northumb. Book, p. 19. It is sometimes used with powder-fort, 38. 156. for which see the next and last article.” — Samuel Pegge. “The Forme of Cury — A Roll of Ancient English Cookery”. 1790.
“Douce” in French means “sweet”.