A bouillon cube is a soup stock made from the evaporation of vegetables, meat and seasonings and shaped into a small cube. Bouillon was one way for Napoleonic armies to preserve soup stock and was rumored to have been discovered by a chef upon returning to his camp fire after a long battle to find his soup had hardened under a slow fire to a solid mass.

Bouillion is also sold in granules and as concentrated stock bases. All are interchangeable.