Pimiento-stuffed olives (also pimento-stuffed olive) are a common garnish used in cocktails and salads, made with a cured green olive stuffed with a pimiento pepper.
Online sources claim a Provencal origin, some 300 years ago, but I have located no credible source for that yet. A branded version was introduced to American markets somewhere around 1898 under the trade name "Pim-Olas". (see Life, volume 31, 1898).