Soul, soul, a soul cake!
I pray thee, good missus, a soul cake!
One for Peter, two for Paul,
Three for Him what made us all!
Soul cake, soul cake, please good missus, a soul cake.
An apple, a pear, a plum, or a cherry, anything good thing to make us all merry.
One for Peter, one for Paul, and three for Him who made us all.
This song is a traditional lyric performed by "mummers," going house to house on and singing in hopes that the mistress of the house would reward them with a soul cake, a small cake usually made with a mixture of oats and flours, and seasoned with spices and dried fruits, in exchange for the singer's prayers for the dead. The idea is that the prayers will assist the departed souls in Purgatory to move on to Heaven. The cakes, and the custom, date back to the Middle Ages in England, and the practice of "souling" is often pointed to as an ancestor of modern day Halloween trick or treat. "Souling" was performed on the Feast of All Souls, Commemoration of all the Faithful Departed, or in Latin commemoratio omnium fidelium Defunctorum.
There are genuine medieval recipes for soul cakes but they're generally not very tasty. They tend to be a bit too heavy with respect to spices, for modern taste. Later recipes are much more like a modern somewhat spicy scone with dried fruit. This page has a modernized version of a recipe from the English recipe compilation referred to as Elinor Fettiplace's Receipt Book. The original recipe from 1604 is as follows:
Take flower & sugar & nutmeg & cloves & mace & sweet butter & sack & a little ale barme, beat your spice, & put in your butter & your sack, cold, then work it well all together, & make it in little cakes, & so bake them, if you will you may put in some saffron into them and fruit.
There's a modern version of the recipe here, as featured on The Food Network.
And here's Sting, from the Today Show, singing the song, with the traditional melody, and some lovely but not quite so ancient additional lyrics.