Pork and Egg Pie
When made not as an individual pie, but as a large loaf-type pie to be sold in portions by the grocer, honest-dealing demands that every single slice have a circle of both egg yolk and egg white in its centre - which has led to the ingeniously odd practice of manufacturing a long tubular form of boiled egg specifically for putting into pies
This pie type has been with us for a long time:
Original Receipt from The Forme of Cury by the Chief Master-Cook of King Richard II, c1390 (Cury 1390)MYLATES OF PORK.
Hewe Pork al to pecys and medle it with ayrenn & chese igrated. do þerto powdour fort safroun & pyneres with salt, make a crust in a trape, bake it wel þerinne, and serue it forth.