Tartar sauce
Tartare sauce (or Tartar sauce) is a thick white sauce made from mayonnaise and finely chopped pickled cucumbers, capers, onions (or chives) and fresh parsley. Chopped hard-boiled eggs, olives, and radish are sometimes added, and mustard sauce is often used as an emulsifier. It is frequently used to season fried sea food dishes. It can also be made by mixing commercially produced mayonnaise.