Black Forest cake

Preheat the oven to 170°C using conventional top and bottom heat. Line the base of a 24 cm springform pan with parchment paper, but do not grease the sides. Have ready a mixer, a large bowl, a sieve, a cooling rack, a long serrated knife, a cake stand, and a piping bag fitted with a star tip. The eggs should be at room temperature; separate the whites from the yolks, making sure no fat or yolk gets into the whites. Sift the cake flour, 40 g cornstarch, and cocoa together. Keep the cream in the refrigerator. Check the quantities of cherries and liquid: you need 600 g fruit after draining and 350 ml liquid, plus an additional 60 ml juice for the alcohol-free version. If there is not enough liquid from the cherries, make up the difference with cherry juice.

Beat the egg whites with a pinch of salt until foamy. Once they begin to hold their shape, gradually add 180 g sugar, a spoonful at a time, while continuing to beat. Beat for a few more minutes until the mixture is thick and glossy and the sugar is barely detectable when rubbed between your fingers. Add the yolks one at a time, mixing briefly on low speed just until combined. Add the dry ingredients in three batches and gently fold them in with a spatula, lifting from the bottom, without prolonged mixing and without using the mixer. Transfer the batter to the pan, level the surface, and bake for about 35–40 minutes. Do not open the oven during the first 30 minutes. The sponge is ready when the center springs back after a light press and a skewer inserted into the center comes out clean. If raw batter remains on the skewer, bake for a few more minutes. Remove the pan and let stand for about 10 minutes, then loosen the edges with a thin knife, remove the ring, and transfer the sponge to the rack.

While the sponge bakes, drain the cherries thoroughly, reserving the liquid. From the measured 600 g fruit, set aside the 12 prettiest whole cherries without pits or stems for decorating; keep them covered in the refrigerator. Measure 350 ml liquid: 250 ml for the filling and 100 ml for soaking the sponge. Take 50 ml from the filling portion and mix with 25 g cornstarch. Bring the remaining 200 ml to a boil with 30 g sugar. Pour in the cornstarch mixture, stirring vigorously, and cook over low heat for about 1 minute until it forms a thick, glossy gel. Add all the remaining cherries, stir gently, and heat for about 1 minute. Transfer to a wide bowl, cover the surface, and leave to cool completely. The filling must be thick and cold before assembly. Separately combine the reserved 100 ml liquid with 60 ml kirsch. For the alcohol-free version, use 60 ml cherry juice instead of kirsch. Do not heat the soaking syrup.

Leave the sponge on the rack until completely cool, usually about 2 hours after taking it out of the oven. Do not cut the cake while it is warm, and do not spread cream onto layers that are even slightly warm. Remove the paper from the base. Use a long serrated knife to cut the sponge horizontally into three even layers, turning the cake and gradually deepening the cut. If the top is slightly domed, trim only the small uneven area. The prepared cherries must also be completely cold; finish chilling them in the refrigerator if needed. Make chocolate shavings with a vegetable peeler or knife and set aside somewhere cool. Have all the sponge layers, cherries, soaking syrup, and decorations ready before whipping the cream so you can assemble the cake promptly afterward.

Sprinkle the gelatin evenly over 50 ml cold water and leave to bloom for about 10 minutes. Dissolve it gently in a warm water bath, stirring; do not boil. The mixture should be liquid and warm, about 35–40°C, not hot or beginning to set. In a chilled bowl, whip 1000 ml cold cream with 80 g powdered sugar to soft peaks. Gradually add 3–4 tablespoons of this whipped cream to the liquid gelatin, mixing thoroughly after each addition to bring the temperatures closer together. Immediately pour the smooth mixture into the remaining cream in a thin stream while mixing on low speed. Beat briefly, just until the cream holds its shape; do not beat until grainy. If the gelatin has set before adding the cream, gently dissolve it again before tempering. Weigh out 220 g cream for each of the two filling layers and about 450 g for coating the cake, then transfer the rest, about 250 g, to the piping bag for 12 rosettes. Work immediately; keep any cream you are not using briefly refrigerated.

Place the bottom sponge layer on the cake stand. Divide the soaking syrup into three equal parts; use a brush or spoon to moisten the bottom layer evenly with a portion, without leaving puddles. Spread the first 220 g cream over it, leaving a slightly higher rim around the edge. Distribute half the cold cherry filling in the center and level gently, leaving a border of cream about 1 cm wide around the edge. Cover with the middle sponge layer, press lightly with an open palm, and moisten with the second portion of liquid. Repeat with the second 220 g cream and the remaining filling. Add the last sponge layer, straighten the cake, and press gently. Moisten the top with the remaining liquid. There should be exactly two filling layers between the three cocoa sponge layers; do not put the cherries reserved for decorating into the filling.

Spread about 450 g of the reserved cream over the sides and top of the cake. First apply a thin layer to trap the crumbs, then add the remaining cream and smooth with a spatula. Cover the lower part of the sides and the center of the top with chocolate shavings, leaving space for the rosettes. Pipe 12 evenly spaced rosettes around the top edge. Pat the 12 reserved cherries thoroughly dry with paper towels so their juice does not run down the cream, and place a cherry on each rosette. The cherries should be without pits and without stems. Put the finished cake in the refrigerator immediately.

Chill the cake for at least 4 hours in a refrigerator at a temperature no higher than 5°C, until the cream and cherries are set and the sponge layers have absorbed the syrup evenly. Cover with a cake dome or box that does not touch the decorations. Do not shorten the chilling time: a freshly assembled cake will be harder to cut neatly. Divide into 12 servings, cutting between the rosettes. Use a long, sharp knife, warming it in hot water and wiping it dry before each cut. Serve chilled and keep the remaining slices in the refrigerator.