Eliza Leslie,
Miss Leslie's Lady's New Receipt-Book…
“ VANILLA BLANC-MANGE.—Chip fine an ounce of the best isinglass, and put it into a small sauce-pan, with a jill of cold water, and boil it till entirely dissolved. In another sauce-pan boil half a pint of rich milk and a vanilla bean. Boil it, (with the lid on,) till the flavour of the vanilla is well extracted. Whip a quart of rich cream to a stiff froth. Separate the whites and yolks of four eggs. Beat the whites till they stand alone. ”
