It's a small cup with a screw on lid that you put a cracked raw egg and whatever other ingredients you like (cheese, bits of bacon, herbs)in, then simmer it in a pan of water. Then you eat the egg out of the cup. Serious yum--and the egg stays really hot. I guess there are modern ones, but you can find pretty porcelain ones, like Royal Worcester, at antique stores really cheap.

You'd only get a really tiny bit of jam!