Here is a recipe from my current grand projet, the Koestlichs New Kochbuch by Anna Wecker. This is an amazing resource for reconstructing kitchen practice and I hope to publish it as a book sometime next year. The translation is about 40-50% done at this point. And here is the lesson I learned experimenting from it:
A tart of strawberries or gooseberries (Kreusel- oder Stichbeeren), whatever they be called
Take eggs, the yolks alone or all together as you wish, beat and whip them well, then take good thick cream that is sweet, stir in as much as there are eggs, add rosewater if you wish, grind of almonds what is right and pass it through (a cloth) with the cream, but in that case take a little more of the milk (cream) than of the eggs. Hold it over a bright fire, but far away, stir it diligently until it begins to thicken a little, but do not let it boil. Then the dish (pastry) should be ready, and it should not be too high, half as high as another tart is. Then pour the mix into it and place nice strawberries or gooseberries in it so that they are half in the mass and half sticking out, and strew it well with sugar so that you neither see the mass nor the berries. The strawberries should be washed in rosewater and not too ripe, for then they turn to mush immediately, but the gooseberries are fine and right when they are already yellow and clear. They need much sugar. Bake them well and give a lot of heat below, but not too much above so that they stay nicely white. It is enough quickly. If you bake them in an oven, lay a piece of paper on top.
I love this recipe: a crisp, thin base, a layer of rich custard, juicy fruit and a glistening sweet crust on the top. It looks so much like a direct ancestor of the perpetual German favourite, Erdbeerkuchen. But when I tried it, what I got was a soggy mess.
The start was promising. The custard held up well, the berries were firm and sweet, and it did not burn or brown much. It was delicious, but spoonable.
I tried it a second time with smaller strawberries, for a baronial feast the following year, and got – broadly similar results. Meanwhile using the remaining custard with a bowlful of redcurrants worked beautifully.
And that is, of course, the explanation. All strawberries marketed today are descended from the large and juice Virginia and Chilean strawberries which are New World plant. Anna Wecker most likely never saw one. She would have worked with the European forest strawberry (fragaria vesca) which produces much smaller, firmer fruit. And that most likely will produce the result I want. With luck, I may be able to manage to try that this year.