
The Canton of Nimenefeld holds an annual event, Cattle Raids, at which one of the competitions is "Best Celtic Use of a Cow". This pie was entered at Celtic Cattle Raids 4, and ended up winning this category.I hadn't originally intended to enter this competition, which is why the documentation for this entry was a little shorter than usual; however, inspiration struck two nights before the event.
To make a pastry dough for all shaped pies - Sabina Welserin - Take flour, the best that you can get, about two handfuls, depending on how large or small you would have the pie. Put it on the table and with a knife stir in two eggs and a little salt. Put water in a small pan and a piece of fat the size of two good eggs, let it all dissolve together and boil. Afterwards pour it on the flour on the table and make a strong dough and work it well, however you feel is right. If it is summer, one must take meat broth instead of water and in the place of the fat the skimmings from the broth. When the dough is kneaded, then make of it a round ball and draw it out well on the sides with the fingers or with a rolling pin, so that in the middle a raised area remains, then let it chill in the cold. Afterwards shape the dough as I have pointed out to you. Also reserve dough for the cover and roll it out into a cover and take water and spread it over the top of the cover and the top of the formed pastry shell and join it together well with the fingers. Leave a small hole. And see that it is pressed together well, so that it does not come open. Blow in the small hole which you have left, then the cover will lift itself up. Then quickly press the hole closed. Afterwards put it in the oven. Sprinkle flour in the dish beforehand. Take care that the oven is properly heated, then it will be a pretty pastry. The dough for all shaped pastries is made in this manner.
To make Pyes. Pyes of mutton or beif must be fyne mynced and ceasoned wyth pepper and salte, and a lyttle saffron to coloure it, suet or marrow a good quantite, a lyttle vyneger, prumes, greate raysins, and dates, take the fattest of the broathe of powdred beyfe, and yf you wyll haue paest royall, take butter and yolkes of egges, and to tempre the flowre to make the paeste. Source [A Proper Newe Booke of Cokerye, Anne Ahmed (ed.)]:
Pies of Paris. Take & cut good pieces of pork, and pieces of veal, together, & put in a good pot, & add fresh broth, & a quantity of wine, & bring to a boil until done; than take it from the fire, & let it cool a little; than add egg yolks, & ginger, sugar, & salt, & minced dates, & currants; then make good pastry, then pie shells, and add; cover the pie, and bake it, and serve. - Austin, Thomas. Two Fifteenth-Century Cookery-Books. Harleian MS. 279 & Harl. MS. 4016, with extracts from Ashmole MS. 1429, Laud MS. 553, & Douce MS 55. London: for The Early English Text Society by N. Trübner & Co., 1888.
Crust:
I began by chopping 2 pounds of beef chuck roast finely, including the fatty portions of the meat. I boiled the beef in broth, then drained the cooked meat and added currents, salt, sugar, ginger, grains of paradise, and saffron, as well as egg yolks to thicken the broth. I then set this mixture aside. Then, I melted 1.5 sticks of butter with an equal amount of water. While this melted, I mixed 3 egg yolks with enough flour to make a pie crust, then added the hot water/butter mixture. (This is not a standard pie crust recipe, but it is the procedure specified by Sabina Welserin for a standing pie crust. It creates a tougher, harder crust than modern pie crust, perfect for making a pie capable of standing on its own. It can be eaten or not, at the diners' choice.)
The pie crust was divided into 3 parts, one slightly larger than the others. The largest piece was rolled out and pressed into a 14th-century replica ceramic pie dish, and the meat mixture was placed into the pie. A second piece was rolled out and placed over the meat, and the coffyn was sealed. I then used the remaining pie crust to create a "Celtic" knotwork pattern on top of the pie.

Instead of following a specific recipe for this pie, I chose elements of several pies to create a tasty dish - all of these pies are similar enough that this sort of "mix and match" is not unreasonable.
My only evidence for pastry decorations such as this is Elizabethan; but knotwork was at least described as being used. This particular design was chosen merely to fit the theme of the competition.