Zwetschgendatschi (Bavarian Plum Sheet Cake)

Zwetschgen are a specific type of plum (Prunus domestica subsp. domestica): small, oval, and deep purple-blue, with a distinct seam down one side. Their flesh is firm, low in juice, and separates cleanly from the pit, which is exactly why Zwetschgendatschi calls for them by name instead of just any plum. Round varieties like greengage or mirabelle plums are usually clingstone and much juicier, so they turn soft and watery in the oven and can soak the dough instead of sitting on top of it. Grocery stores sometimes sell the same fruit as Italian plums or prune plums. Damson plums work as a substitute, though they are more tart and slightly smaller.

Yes, but drain them well first. Thaw the plums fully in a colander set over a bowl for at least 30 minutes, pressing gently to release the extra liquid that freezing forces out of the cell walls. Pat them dry with a kitchen towel before arranging them on the dough, otherwise the released juice pools under the fruit and turns the base gummy. Frozen plums also collapse faster in the oven than fresh ones, so check the cake at the 20-minute mark rather than waiting the full 25 to 30 minutes. Fresh Zwetschgen in late summer will always give a firmer bite, but frozen ones get you the cake in the middle of winter.

The most common cause is skipping the second rise: if the dough goes into the oven still dense and unproofed, it cannot cook through evenly under 1.3 kg of juicy fruit. Give the shaped dough a full 45 to 60 minutes in a warm spot until it looks visibly puffed before you even cut the plums. The second cause is too much fruit juice with no way to escape: a layer of butter streusel on top actually helps here, because it absorbs and holds the released juice instead of letting it run down into the dough. Baking on the middle rack, not the lower one, and preheating the oven fully to 200°C also matters more than it seems, since a cool oven means the base sets too slowly. If it still happens, next time roll the dough about 1 cm thicker at the center rather than paper-thin.

The original Augsburg version, documented since the 18th century, is a plain shortcrust base topped only with the plums and no streusel at all. Today most bakeries and home bakers add a butter streusel of flour, sugar, butter, and vanilla, which is why it now reads as the classic version to most Germans. Streusel does more than add crunch: it soaks up the juice that very ripe plums release in the oven, so many bakers add it specifically when the fruit looks especially juicy. If you skip it, dust the finished cake with vanilla sugar the moment it comes out of the oven, while the surface is still warm enough for the sugar to cling.

At room temperature, loosely covered, it stays good for about 2 days before the crumb starts to dry out and the fruit starts to weep more. In the fridge, wrapped, it keeps for up to 4 days, though the base softens as it absorbs moisture from the plums. For longer storage, freeze individual squares wrapped in foil for up to 2 months, then thaw at room temperature for about an hour and warm briefly at 160°C to bring back some crispness at the edges. It does not respond well to the microwave, which turns the yeast dough rubbery instead of tender.