It is essentially a partially dehydrated broth and a solid counterpart of the glace de viande (meat glaze) used in French cuisine.

Once it was sufficiently gelatinous to hold its form, it was placed on pieces of flannel or unglazed earthenware dishes and rotated regularly to dry it further.

In the late sixteenth century, Sir Hugh Plat wrote, in his unpublished notes, of portable soup as a potential military rations for the army and navy, describing it as meat broth boiled down to a thick and dry paste which he called "gelly".

Alternatively, the dry jelly could be "stamped" into shape with a wooden die, like the "Genoa Paste" of quinces familiar to Plat and other cooks of the time.

The jelly was variously described by Plat as a "Victual for Warr", "dry gelly carried to the sea", and a food for soldiers on the march.

)[citation needed] As a mass-produced product, portable soup is generally held to have been invented by Mrs Dubois, a London tavern keeper who, with William Cookworthy, won a contract to manufacture it for the Royal Navy in 1756.

A similar product, portable gelatin, was developed by American inventor Peter Cooper in 1845, as a staple meal or dessert for families.

Nevertheless, as late as 1881 portable soup was still being described by the Household Cyclopedia as: exceedingly convenient for private families, for by putting one of the cakes in a saucepan with about a quart of water, and a little salt, a basin of good broth may be made in a few minutes.