Zwetschgenkuchen

Method

1. Warm the milk to about 35°C, no hotter than you can hold a finger in. Crumble the fresh yeast into it with a teaspoon of the sugar and leave it 10 minutes until it foams. If you are using instant dry yeast, mix it straight into the flour and skip this step.
2. Put the flour, remaining sugar, salt, and lemon zest in a bowl. Add the milk, the egg, and the soft butter and knead 8 minutes by machine or 12 by hand. The dough is ready when it pulls away from the bowl in one piece and springs back slowly when you press it. It should be soft and slightly tacky, not stiff.
3. Cover and let it rise at room temperature for 60 to 75 minutes, until it has clearly doubled. A cold kitchen can take two hours. Rushing this on top of a radiator gives you a yeasty smell and a coarse crumb.
4. While it rises, wash the plums, cut them along the seam, twist the halves apart, and lift out the stones. Do not wash them until you are ready to use them: the white bloom on the skin protects the fruit. Leave the halves cut side up on a tray lined with paper so the surfaces dry a little.
5. Butter the sheet. Knock the dough back, roll it directly on the sheet to the corners, and let it come back to the edges with your fingertips. It should be 5 to 7 mm thick and no thicker. This is a fruit cake with a dough under it, not a bread with fruit on top.
6. Scatter the semolina evenly over the whole surface of the dough. It looks like too little. It is not.
7. Lay the plum halves on cut side up, skin down, overlapping in rows like roof tiles, packed tight enough that no dough shows. Press each one only lightly into the dough. Hard pressing tears the surface and gives the juice a way in.
8. Let the assembled sheet rest 25 minutes, uncovered, while the oven heats to 190°C top and bottom heat, 170°C fan. Put a rack in the lower third.
9. Bake 35 to 40 minutes. It is done when the exposed dough at the rim is deep golden and the plum juice at the surface has gone glossy and slightly syrupy, with a few darkened tips on the fruit. Two minutes past this point the juice starts to catch and turn bitter at the edges of the sheet, so watch it from minute 33.
10. Mix the sugar and cinnamon. Dust the cake with it the moment it comes out, while the surface is still wet enough to hold it.
11. Slide the cake, on its paper, onto a rack and cool it uncovered. Never cover a warm plum cake. The steam condenses on the cling film, runs back down, and softens the top you just crisped.
12. Serve it warm or barely lukewarm, cut into squares, with unsweetened whipped cream. The cake carries enough sugar for both.

Notes

• Zwetschgen are not Pflaumen, and the difference decides whether this works. Zwetschgen are the oval, blue-violet, tapered fruit sold in Germany from August to October. The flesh is firm and yellow-green, it lets go of the stone cleanly, and it holds its shape in the oven. Pflaumen are round, softer, sweeter, wetter, and cling to the stone, and in a sheet cake they collapse and flood the dough. In Canada, buy Italian prune plums, which are the same fruit under a different name and turn up in Ontario and BC from late August. Damsons work as well and are sharper. Do not buy the big round black or red supermarket plums for this. If they are all you can get, cut them into quarters, salt them lightly, drain them 30 minutes in a sieve, pat them dry, and double the semolina to 100 g.
• The soggy bottom, and what actually fixes it. Four things get blamed and only three are worth doing. First, the scattered layer between dough and fruit: fine semolina, ground almonds, or dry breadcrumbs. All three absorb juice, and all three work, but they are not equal. Semolina swells into the juice and stays granular, which is why I use it. Ground almonds taste better and absorb slightly less, so use 60 g if you go that way. Dry breadcrumbs are the weakest of the three because they turn pasty and you can taste them. Second, arrange the fruit cut side up. The skin is a waterproof barrier, so skin-down means the juice that renders has to travel up and out as steam instead of down into the dough. Some Bavarian bakers lay them cut side down for a neater look, and their cakes are wetter underneath. Third, bake in the lower third at a real 190°C so the base sets before the fruit gives up its water. Fourth is the one that does nothing: brushing the dough with egg white. It sounds sensible, it is in a lot of blog comments, and it makes no measurable difference under a kilo and a half of fruit.
• Three doughs, and why this one. Hefeteig is the traditional base in Swabia and Bavaria and it is the one that suits a full sheet, because it stays light under a heavy fruit load and it soaks up a little juice without going to mush. The two alternatives, with quantities for the same 30 by 40 cm sheet:
  • Mürbeteig, shortcrust, crisper and more like a tart: 400 g flour Type 405, 200 g cold diced butter, 130 g sugar, 1 egg, 1 pinch of salt. Rub to crumbs, work in the egg, press into a disc, chill 30 minutes, then press it 4 mm thick into the sheet. Prick it all over, semolina, fruit, and bake at 180°C for 35 to 40 minutes. It is the better choice if you want to cut neat pieces cold the next day.
  • Rührteig, a creamed batter, softest and quickest: 250 g soft butter, 200 g sugar, 4 eggs, 300 g flour Type 405, 15 g baking powder, 100 ml milk. Cream butter and sugar, beat in the eggs one at a time, fold in the flour and baking powder with the milk, spread on the sheet. Drop the fruit to 1.2 kg because the batter rises around it, and bake at 180°C for 40 to 45 minutes. This one does not need the semolina; the batter absorbs the juice itself.
• Streusel are optional and they change the cake. With them it is closer to a crumble and it keeps a day longer; without them the fruit is the whole flavour and the top stays sharp. If you make them, rub the flour, sugar, vanilla sugar, salt, and cold butter together with your fingertips until you have lumps the size of peas and hazelnuts mixed, then scatter them over the fruit before baking and add 5 minutes to the time. Do not work them into a paste. Warm hands are the enemy; if the mixture goes greasy, chill it 15 minutes and start pinching again.
• Eat it warm, with a lot of unsweetened whipped cream. This is not a garnish decision. Warm plum and cold cream is the point of the dish. And it is not only a dessert: in Swabia a piece of warm Zwetschgenkuchen with coffee counts as a Vesper and can stand in for a meal, and in the Palatinate the same cake is eaten at lunch with potato soup.
• The cake keeps two days at room temperature under a tea towel, never under plastic. It does not improve in the fridge. It freezes well in cut pieces: wrap them individually and reheat from frozen at 160°C for 15 minutes, which brings the top back.
• Zwetschgen freeze better than almost any other fruit. Halve and stone them in September, freeze them flat on a tray, then bag them. Lay them on the dough still frozen, add 5 minutes to the bake, and go up to 80 g of semolina, because they shed more water than fresh.

Sources used

• Dr. Oetker: Zwetschgenkuchen vom Blech
• Dr. Oetker: Schwäbischer Zwetschgenkuchen mit Bröseln
• Sheepy’s Bakery: Zwetschgendatschi mit Hefeteig
• Sheepy’s Bakery: Zwetschgen vs. Pflaumen
• Maria es schmeckt mir: Saftiger Zwetschgendatschi, das Originalrezept aus Hefeteig
• Brotwein: Zwetschgenkuchen mit Streusel und Hefeteig vom Blech
• Kochen Kunst und Ketchup: Schwäbischer Zwetschgenkuchen
• t-online: Pflaumen und Zwetschgen zum Backen, ist eine Frucht besser geeignet?
• Bäckerei Spiegelhauer: Zwetschge, Pflaume, Mirabelle, womit Pflaumenkuchen backen?
• Wikipedia: Zwetschgenkuchen