1,056. The Food for an Eiruv Tavshilin

Shvisas Yom Tov 6:3

The minimum volume needed for an eiruv tavshilin is an olive-sized portion of food. This amount is sufficient whether for a one person or for 1,000 people. The eiruv may not be made with bread, grain or similar things; one must use a portion of cooked food that is served with bread, like meat, fish, eggs, etc. Even lentils left over in the pot are sufficient for this purpose. One might even use the fat that remains on a knife after cutting roasted meat. If the volume of an olive of such fat is left when scraping off the knife, it may be used for an eiruv tavshilin.

Shvisas Yom Tov 6:4

A cooked food for an eiruv tavshilin includes food that was roasted, stewed, pickled or smoked, and even small fish that are made ready to eat simply by pouring hot water over them.