The salted and pickled caper bud (also called caper and gabbar for Turkish Cypriots) is often used as a seasoning or garnish. Capers are a common ingredient in Mediterranean cuisine, especially Cypriot and Italian. The mature fruit of the caper shrub is also prepared similarly, and marketed as caper berries.
The buds, when ready to pick, are a dark olive green and about the size of a kernel of corn. They are picked, then pickled in salt, or a salt and vinegar solution, or drained. Intense flavor is developed, as mustard oil (glucocapparin) is released from each caper bud. This enzymatic reaction also leads to the formation of rutin often seen as crystallized white spots on the surfaces of individual caper buds.
Capers are a distinctive ingredient in Italian cuisine, especially in Sicilian and southern Italian cooking. They are commonly used in salads, pasta salads, pizzas, meat dishes and pasta sauces. Examples of uses in Italian cuisine are chicken piccata and salsa puttanesca.
Capers are also known for being one of the ingredients of tartar sauce. They are also often served with cold smoked salmon or cured salmon dishes (especially lox and cream cheese). Capers are also sometimes substituted for olives to garnish a martini.
Capers are categorized and sold by their size, defined as follows, with the smallest sizes being the most desirable: Non-pareil (up to 7 mm), surfines (7-8 mm), capucines (8-9 mm), capotes (9-11 mm), fines (11-13 mm), and grusas (14+ mm).
Unripe nasturtium seeds can be substituted for capers; they have a very similar texture and flavour when pickled. Pickled caperberries are also very popular as a snack in Menorca.
If the caper bud is not picked, it flowers and produces a fruit called a caperberry. The fruit can be pickled and then served as a Greek mezze.
In addition, the Greeks make good use of the caper’s leaves, which are especially desirable and hard to find outside of Greece. They are pickled or boiled and preserved in jars with brine cf. caper buds. Caper leaves are excellent in salads and in fish dishes. Dried caper leaves are also used as a substitute for rennet in the manufacturing of high quality cheese.