I have noticed that to a certain amount of people making a multi-layered cake is somehow overwhelming. They end up just liking a cake and moving on, never attempting to make one. Baking this cake is nothing to hold your breath for. Yes, it does take a bit of time and some simple kitchen accessories (a mixer and springform pans for example), but in the end, it is really made of 9 main ingredients (plus some spices). Still, the result is just majestic. The flavors are awesome, shortly put. The chocolate-cherry combination wins most of the hearts. Go for it.
The cake originated in Germany where you can find Black Forest mountain range. Its name hasn’t derived from there, though; but rather from a liquor distilled from cherries. This liquor is, originally, the special ingredient in the dessert which primarily consists of chocolate sponge cake, whipped cream, and cherries. You see, it is quite basic and straightforward.
Naturally, I’ve taken some of the recipes out there and created a low-carb, sugar-free version of Black Forest cake. Here in Europe we mostly put sour cherries inside. The sour taste combines super well with the sweetness of chocolate and cream. Using cherries, I can not call this cake keto-friendly, but to some of the ketonians, a piece could still fit inside your macros.
How to simplify the recipe
For the sake of the original cake having 3 sponge cake layers, I’ve made the same number of layers. But you don’t necessarily have to do the same. You can keep 2 thick layers or cut 2 thick layers in half to make 4. This depends on you, but take into consideration the size of baking pans. If wider than 9″, I’d see no problems in keeping 2 thick layers. 8″ or less, I’d use a cake slicer to make 4 layers. Besides, the smaller the cakes, the easier it is to cut them lengthwise.
Because you need to bake the sponge cakes immediately after mixing the butter in, but the two might not fit on the middle oven rack together (again, depending on the size of the pans), you might need to bake in upper and lower rack simultaneously. If this is the case, I recommend using the fan in the oven (if possible) and lowering the baking temperature for 20°F.
And do not forget: Keeping the ingredients for the sponge cake at room temperature is important information to follow. For the contrast, before mixing heavy whipping cream, it always helps to take the cream straight from the fridge and to place the mixing bowl in the freezer 15 minutes prior to mixing.
Yes, you can use whatever type of cherries you find. I buy frozen sour cherries and unfreeze them. That works work great. I would be extra careful buying canned cherries, though. They seem to contain lots of sugar.
Sponge cake layers
- 3 packets powdered gelatin
- 3.5 cups heavy whipping cream
- 1 tbsp cherry vodka or rum
- 2 oz. powdered erythritol
- 1 lb. pitted sour cherries
- 3 tbsp. cherry vodka or rum
- 2 oz. 90% dark chocolate
Sponge cake layers
- Preheat the oven to 350°F (180°C). If you are going to use the fan, 320°F (160°C) should be enough.
Line the bottoms of two 8" or 9" springform pans with parchment paper.
- Using a stand electric mixer, beat 9 eggs with the whisk attachment for 1 min on high speed. With the mixer on, gradually add 1 cup erythritol and continue beating on high speed a full 8 min. It will be thick and fluffy. Tip: You will need a huge mixing bowl.
- Whisk together almond flour, cocoa powder, and cinnamon and sift in thirds into batter. Fold with a spatula between each addition. Once all flour is in, continue to fold just until no streaks of flour remain, scraping the bottom of the bowl to get any pockets of flour. We do not want to over-mix and deflate the batter.
- Gently fold in ½ Tsp vanilla and room temp. butter, folding as you add butter in a steady stream and scraping from the bottom to make sure you don't have butter pooling at the bottom. Fold just until incorporated.
Pour 1/3 and 2/3 of batter into the prepared pans (the 2/3 is going to be split in two when baked).
Bake immediately for 20 minutes, or until a toothpick comes out clean. If the batter is not baked straight away after mixing, it might deflate.
- Let cool in pans for 10 min then run a thin spatula around edges to loosen cake. Transfer to a wire rack and remove parchment paper. When cakes are at room temp, take the thicker one and divide it in half lengthwise using a cake slicer or a long sharp knife.
Cherry filling and syrup
- Roughly chop pitted sour cherries and place in a medium bowl with 3 Tbsp. cherry vodka or rum. Let sit at room temp for at least 30 min, stirring a couple of times. Drain cherries in a sieve over a bowl. Keep the cherries and syrup. You should get about ¾ cup total syrup. If not, add some water.
- Dissolve gelatine according to instructions.
Beat heavy cream with the whisk attachment on high speed until soft peaks form. Add powdered erythritol and 1 tbsp. cherry vodka (or rum) and beat on high for another minute. Add dissolved gelatine and beat for another minute or two until stiff and spreadable.
Assembling the cake
- Place first sponge cake layer on a cake stand and brush with 1/3 of the syrup. Cover top with about 1 cup frosting and top with 1/2 of the chopped cherries. Repeat with remaining layers and top with the flattest layer. Fill the cracks along the sides of cake with frosting then frost the top and sides with remaining frosting.
Leave some of the frosting in a piping bag in the fridge for the top frosting (optional).
- The easy way out here is to use a potato peeler and shave the chuck of chocolate. The not so easy way is to melt the chocolate, spread it on a piece of parchment paper and freeze it. When hardened, use a food scraper to create bark-like shavings.
- Cover sides and top of cake with chocolate shavings leaving a 1" perimeter on top for piping frosting (optional). Refrigerate cake for at least 4 hours or overnight before serving.