Wikipedia

The marshmallow is a confection that, in its modern form, typically consists of sugar or corn syrup, water, gelatin that has been softened in hot water, dextrose, and flavorings, whipped to a spongy consistency. One commonly proposed theory about the origin of marshmallow holds that the traditional recipe used an extract from the mucilaginous root of the marshmallow plant, a shrubby herb (''Althaea officinalis''), instead of gelatin; the mucilage was used to soothe sore throats. Candy USA! However, while concoctions of all parts of the plant have been used as medicine, a more likely origin for the modern sweet can be found in old recipes: Stems of marsh mallow were peeled to reveal the soft and spongy pith with a texture similar to manufactured marshmallow. This pith was boiled in sugar syrup and dried to produced a soft, chewy confection.Rohde, Eleanour Sinclair; A garden of Herbs, Hale Cushman & Flint, 1936 Commercial marshmallows are a late-nineteenth-century innovation. Since Doumak's patented extrusion process of 1948, marshmallows are extruded as soft cylinders, cut in sections and rolled in a mix of finely powdered cornstarch and confectioner's sugar (icing sugar). Not all brands coat their marshmallows in confectioner's sugar.

Read more at Wikipedia...