As BBC Future let him know, a recipe for minced pies first appeared in “print” prior to the dates of print, as it was introduced on a 1390 scroll. (Gutenberg didn’t come up with his history-changing invention until the next century). However, they are not yet called mince pies, but are instead referred to by the fond nickname “meat tartes”. This recipe calls for pork, cheese, and hard-boiled egg mixed with sugar, spices, and saffron, a combination that actually sounds a bit tastier than today’s minced meat. Another recipe, dating from the early 17th century, calls for lamb, suet, currants, raisins, prunes and dates flavored with orange zest, cloves and mace. The 17th century also marked the era when meat pies began to be mentioned as a Christmas dish.
Over the course of time, the minced meat becomes, well, less meat. As food historian Annie Grey, Ph.D. told AllRecipes, in late Tudor times, mince pies had 30% to 50% meat. But in the late 19th century, they generally didn’t contain any meat, although before their invention shorten vegetables they are necessarily made of beef suet. (Fortunately, not too many 19th-century vegetarians protested.) As to why mince pies lost their meat, Gray suggests it happened as part of a culinary evolution that led to the loss of meat. We begin to separate our main dishes from dessert and decide that the former should be savory, the latter sweet, and rarely should the two meet.
https://www.mashed.com/711160/mince-pies-have-been-around-longer-than-you-might-think/ Mince Pies has been around longer than you might think