Schwarzwälder Kirschtorte

Method

1. Rub the flour, sugar, salt, and cold butter together to coarse crumbs, work in the egg yolk, and press the dough into a flat disc. Wrap it and chill 30 minutes. Do not knead it warm or the base bakes hard instead of short.
2. Heat the oven to 180°C. Roll the dough out on a sheet of parchment to a 26 cm round about 3 mm thick, using the ring of the springform as a cutter. Prick it all over with a fork, slide the parchment onto a tray, and bake 12 to 15 minutes until it is dry and just colouring at the edge. Cool it flat on the paper. It crisps as it cools.
3. Butter the base of the 26 cm springform and line it with parchment. Leave the sides bare so the sponge has something to climb.
4. Whisk the eggs, sugar, and salt over a pot of hot water until the mixture is warm to the touch, then take it off the heat and beat on high for 10 to 12 minutes. It is ready when the batter falls from the whisk in a ribbon that sits on the surface for a few seconds. This aeration is the only leavening in the cake, so give it the full time.
5. Sift the flour, cornstarch, and cocoa together over the eggs in three additions and fold each one in with a spatula. Cut down through the middle, sweep along the bottom, turn the bowl. Stop the moment the last streak of cocoa disappears.
6. Pour into the tin, level the top, and bake 35 to 40 minutes. A skewer should come out clean and the centre should spring back. Do not open the oven in the first 25 minutes.
7. Run a knife around the edge, release the ring, and cool the sponge upside down on a rack. Leave it at least 4 hours, ideally overnight. A warm or fresh sponge tears when you split it.
8. Drain the cherries and keep the juice. Set 12 cherries aside for the top. Bring 250 ml of the juice to a simmer with the sugar. Stir the cornstarch smooth into the remaining 50 ml of cold juice, whisk it into the pot, and cook 1 minute until thick and clear. Take it off the heat, stir in the drained cherries and 20 ml Kirschwasser, and cool completely. It has to be cold before it touches cream.
9. For the soak, boil the water and sugar for 30 seconds, cool it, then stir in 80 ml Kirschwasser. Adding the spirit off the heat keeps the alcohol and the cherry aroma in the cake instead of in your kitchen.
10. Split the sponge into three even layers with a long serrated knife or a cake wire.
11. Whip the cream with the powdered sugar, vanilla sugar, and stabilizer until it holds a firm peak. Stop while it still looks glossy. Overwhipped cream turns grainy and will not pipe.
12. Set the shortcrust base on the serving plate. Pipe a ring of cream around its outer edge to build a dam, spread a thin layer of cream inside it, and fill with all of the cherry mixture. The cherries sit on pastry, not on sponge, which is the whole reason the base is there.
13. Add the first sponge layer and brush it with a third of the soak. Spread a generous layer of cream. Add the second layer, brush with soak, and spread cream again. Top with the third layer, cut side down, and brush with the last of the soak.
14. Coat the top and sides with cream, keeping a good cupful back for piping. Pipe 12 rosettes around the rim.
15. Press chocolate shavings onto the sides and scatter the rest over the top. Set a cherry on each rosette and dust with powdered sugar.
16. Chill at least 1 hour before cutting. Cut with a long knife dipped in hot water and wiped between slices.

Notes

• The Mürbeteig base stays in. Its job is to sit under the wet cherry filling and not absorb it, so the bottom of the torte holds its shape for three days instead of turning to mush by the second afternoon, and it gives you something rigid to slide the finished torte off. The Leitsätze für Feine Backwaren name it directly: for the bottom layer, shortcrust is also used. Dr. Oetker, the Hochschwarzwald tourist board, and the Hoch-Schwarzwald recipes all build it this way; the versions that skip it put a sponge layer in contact with the cherry juice instead, which is why those tortes are best eaten the day they are cut.
• The sponge ratio is 8 eggs to 260 g of dry, with about a quarter of the dry weight as cornstarch. Per egg that is roughly 32 g of dry, the low end of the classic Wiener Masse proportion, which is what lets it drink 140 ml of soak without turning to paste. The total went up from 6 eggs because a 26 cm tin is 531 cm² and a 6 egg batter bakes to about 4.5 cm there, which gives three layers of barely 1.3 cm once the knife takes its share. Eight eggs bake to about 6 cm and split into three layers of 1.7 cm, which is what you want. Failure looks like this: too little dry and the layers compress into wet sheets under the cream and the torte leans; too much dry and the sponge shrugs off the soak and eats like a dry chocolate cake. There is no baking powder, which is Konditorei practice. If you are not confident whipping whole eggs, sift in 1 level teaspoon as insurance and accept a slightly coarser crumb.
• The 40 g of cocoa is not just for colour. The Leitsätze require the dark sponge to contain at least 3% cocoa powder by weight of batter; at 40 g in about 920 g of batter this sits at 4.3%, clear of the line.
• Kirschwasser is not optional and not a stylistic choice. The Leitsätze do not set a number, they set a taste: the Kirschwasser must be clearly perceptible. German food inspectors work to roughly 50 ml per 2 kg of finished torte as the practical floor, and this one weighs close to 3 kg, so the 100 ml here is a real amount rather than a gesture. Dr. Oetker uses 100 ml, Lecker and Einfach Kochen use around 135 ml. Anything made with cherry liqueur, cherry syrup, or rum is a chocolate cherry cake, which is fine, but it is not this cake. Buy a real Schwarzwälder Kirschwasser from a Baden distiller if you can.
• Sauerkirschen, not sweet cherries. The Leitsätze specify whole or chopped sour cherries with no added flavourings. Schattenmorellen in a 720 ml jar are in every German supermarket. Keep the jar juice: a 720 ml jar gives you about 350 ml once the fruit is out, and that juice thickened with cornstarch is the filling. Do not put jar juice in the soak, it is sugary and it dilutes the Kirschwasser. In Canada, look for jarred Morello cherries at a Polish, Hungarian, or German grocer, or use frozen sour cherries with 300 ml of unsweetened tart cherry juice. Sweet cherries from a tin make the cake cloying.
• Yes, the cream needs Sahnesteif at this volume. One litre of German 30% Schlagsahne will not hold a piped rosette or a cut edge overnight on its own. The standard dose is one 8 g sachet per 250 ml, so four sachets. Canadian 35% whipping cream is stiffer and often manages without. To use gelatin instead, soften 8 sheets in cold water, dissolve them gently, temper with a few spoons of the whipped cream, and fold that back in.
• Make the shortcrust base and the sponge a day ahead. Both keep fine wrapped at room temperature, and the build then takes about an hour. The assembled torte is best on day two, once the soak has spread through the layers, and it keeps 3 days covered in the fridge.
• For chocolate shavings, drag a wide vegetable peeler along the flat side of a bar of chocolate that has sat 20 minutes at room temperature. Straight from the fridge it splinters.

Sources used

• Dr. Oetker: Schwarzwälder Kirschtorte mit Mürbeteigboden
• Hochschwarzwald: Rezept Schwarzwälder Kirschtorte
• Rezeptschachtel: Schwarzwälder Kirschtorte, das Originalrezept aus dem Hoch-Schwarzwald
• Lecker: Schwarzwälder Kirschtorte, klassisch nach Omas Art
• Einfach Kochen: Original Schwarzwälder Kirschtorte
• Sallys Blog: Schwarzwälder Kirschtorte
• Küchencottage: Mürbeteigboden für Torten, Grundrezept
• Kuchenfee Lisa: Schokoladen Biskuit Boden
• Hexenküche: Schoko Biskuit Grundrezept
• Familienkost: Hoher Biskuitboden zum zweifachen Teilen
• Baktotaal: Alles was du über Sahnesteif wissen musst
• CVUA Baden-Württemberg: Getreide, Backwaren und Teigwaren, Leitsätze für Feine Backwaren
• LAVES Niedersachsen: Weltweit beliebt und nach strengen Vorgaben gebacken
• Wikipedia: Schwarzwälder Kirschtorte