At least going by the recipe collection of Philippine Welser, it was a very popular dish:
24 If you want to make an apple tart
Take good apples. Cut about eight slices from each apples, depending on how large they are, and turn them in flour. Fry them, but not as thoroughly as other apple slices. Then lay them out on a tart base and put on another (layer) until the tart base is full. Then take raisins, cinnamon and sugar and strew that on it. Then lay on another layer of apples and strew it again as before. Then put on a thin cover (deckalin) and cut it as you wish. Close it and brush it with egg, and let it bake.
25 If you want to make an apple tart
Take good apples, peel them, and cut them into small slices. Fry (schwems, lit. float) them in fat until they turn brown. Then lay them out on a plate (struck out: on the tart base) and let them cool. Then lay them out on the tart base close together twice (two layers?). After that, take sugar, cinnamon, and a little ginger and sprinkle it all over. Also take raisins. Prepare a cut cover to go on top, brush it with egg, and bake it gently in a tart pan.
26 If you want to make a tart of pureed apples
Take good apples and steam (depf) them until you can pass them through a cloth. Then put them into a bowl and add cinnamon, ginger, and sugar, pour it out on a tart base and bake it nicely. When it firms up well and is about half baked, take rosewater and brush it all over. You can also do this with pears or quinces, or add quinces to this. Also adding a little grated bread is good. Let it bake slowly.
27 If you want to make a tart of chopped apples
Take good, aromatic (wol geschmackt) apples and peel them and chop them small. When they are chopped, take cool fat the size of an egg and melt it in a pan. Then take the chopped apples and add a good handful of raisins and cinnamon and stir it well together. Then put it into the pan into the warm fast and stir it. Take it out into a clean container and sugar it well, and let it cool. Spread it on the tart base, make a cover over it and let it bake. When it is half baked, take it out and pout marrow from the legbone (?marckt Ausem bay) on it, and if you have no marrow, take butter, and let it bake.
This is not quite as varied as the recipes for milk tart, but clearly there were many ways of putting apples into a pie. Interestingly, all of them involve what seems to have been the expected flavour profile – apples go with cinnamon. Further, even allowing for the fact that these were not the crisp, sweet dessert apples we are used to, these fried and sweetened fillings must have been enormously rich and heavy.
Philippine Welser (1527-1580), a member of the prominent and extremely wealthy Welser banking family of Augsburg, was a famous beauty of her day. Scandalously, she secretly married Archduke Ferdinand II of Habsburg in 1557 and followed him first to Bohemia, then to Tyrol. A number of manuscripts are associated with her, most famously a collection of medicinal recipes and one of mainly culinary ones. The recipe collection, addressed as her Kochbuch in German, was most likely produced around 1550 when she was a young woman in Augsburg. It may have been made at the request of her mother and was written by an experienced scribe. Some later additions, though, are in Philippine Welser’s own hand, suggesting she used it.
The manuscript is currently held in the library of Ambras Castle near Innsbruck as PA 1473 and was edited by Gerold Hayer as Das Kochbuch der Philippine Welser (Innsbruck 1983).