Parental Advisory: The passage quoted from the Elizabethan playwright Thomas Fletcher contains obscure references that will probably go right over the heads of most kids. Still, you may want to preview this one if you're reading to children.
No one really knows where mince pies originated, but it is thought that they must have decended from some ancient Roman custom. What is known is that mince pies became a regular part of Christmas celebrations as early as the 16th century, when mince pies were coffin or cradle shaped, rather than round as they are now. At that time, they contained quite a bit of shredded meat in addition to the usual melange of dried fruits.
The only superstition associated with mince pies to survive to this day is this: for every mince pie eaten between Christmas Day and Twelth Night, the eater will have one perfectly happy month during the coming year. Doing the math, it's then possible to ensure a wholly happy year simply by eating a quantity of mince pies at Christmas.
Not everyone likes mince pies; Thomas Fletcher could certainly be numbered among the detractors:
The cloyster'd steaks with salt and pepper lye
Like nunnes with patches in a monastrie.
Prophanenesss in a conclave? Nay, much more,
Idolatrie in a crust! Babylon's whore
Rak'd from the grave, and baked by hanches, then
Serv'd up in coffins to unholy men:
Defil'd with superstition, like the Gentiles
Of old that worship'd onions, roots, and lentils!