A devil’s food sheet cake with cherry pie filling folded through the batter, frosted with German buttercream and finished with ganache.
Twelve to fifteen servings, and two and a half hours including cooling and decorating.
Temper the eggs, or you get scrambled custard
A little hot milk whisked into the egg and cornstarch mixture, then the rest added gradually.
This is the step that decides whether the German buttercream works. Eggs set at around 160F, and hot milk poured straight into them cooks them into visible curds before they can be whisked in.
Adding a small amount first raises the egg mixture’s temperature gently. Once it is warm, the rest can go in faster.
If you do get lumps, pushing the custard through a fine sieve before cooling rescues it.
Whisk constantly while it thickens
Returned to the pan over medium heat.
Cornstarch thickens fast once it reaches temperature, and the mixture goes from liquid to thick in under a minute. Stop whisking for a moment and the bottom sets against the pan.
Get into the corners of the pan with the whisk. That is where it catches first.
Plastic wrap on the surface
Pressed directly against the custard, not stretched across the bowl.
A custard cooling with air above it forms a skin, and that skin then breaks into rubbery pieces when you beat it into the butter.
Directly on the surface means no air contact and no skin.
Both components at the same temperature
Softened butter beaten light and fluffy, then the cooled custard added gradually.
German buttercream splits if the custard and butter are at different temperatures. Cold custard hitting whipped butter makes the butter seize into lumps; warm custard melts it.
Both at room temperature is the requirement. If it does look split, keep beating; it usually comes back together.
Fold the cherry filling, do not mix it
A 21 ounce can folded into the cake batter along with the chocolate chips.
Folding keeps the cherries whole, which is what gives you fruit through the finished cake. Beating them into the batter breaks them down and you get a pink-tinged chocolate cake with no distinct cherry.
Use a spatula and turn the bowl rather than stirring in circles.
A few moist crumbs on the toothpick
Thirty to thirty five minutes at 350F.
Not clean. A cake with a can of pie filling in it stays moist, and baking until a toothpick comes out clean means overbaking.
Avoid testing through a cherry, which reads wet regardless.
Chill the buttercream before the ganache
Twenty minutes in the fridge after frosting.
Ganache poured onto soft buttercream sinks into it and the two blend into a muddy layer. Chilled, the buttercream is firm enough to hold the ganache on top as a distinct layer.
The notes make this point and it is what gives the clean bands in a cross section.
Cool the ganache slightly too
After stirring smooth, before pouring.
Hot ganache melts the surface of even a chilled buttercream. Slightly cooled it is still pourable but no longer hot enough to do damage.
Heat the cream until hot but not boiling. Boiling cream can make ganache grainy.
The cake is better the next day
The notes say so and it is true of most chocolate cakes.
The crumb settles, the moisture from the pie filling distributes evenly, and the buttercream firms into something that slices cleanly.
Around 520 calories per serving, which the source gives as approximate.
Storing
Covered in the refrigerator up to five days, or individual slices frozen up to three months. <p>Thaw frozen slices overnight in the fridge rather than at room temperature, which makes the ganache sweat. ## Why German buttercream It is custard beaten into butter, which makes it less sweet than American buttercream and lighter than Swiss meringue. Against a rich chocolate cake and a ganache layer, that restraint matters.
It is also more fragile. It softens at room temperature faster than other buttercreams, which is why this cake lives in the fridge.
Garnishing
Fresh or maraschino cherries, chocolate curls, mini chips or whipped cream. Add them just before serving; fresh cherries weep and whipped cream slumps if they sit on a chilled cake for hours.
Black Forest Sheet Cake
Description
A layered black forest sheet cake with cherry chocolate cake, vanilla German buttercream and ganache.
Ingredients:
Instructions
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Whisk together 1/4 cup of the sugar and the cornstarch in a heatproof bowl, add the 2 eggs and whisk until smooth.
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In a saucepan heat the 1 cup of milk with the remaining 1/4 cup sugar until it begins to simmer. Slowly whisk a little hot milk into the egg mixture to temper it, then gradually add the rest.
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Return the mixture to the saucepan and cook over medium heat, whisking constantly and getting into the corners, until thickened. Remove from the heat and stir in the 2 tablespoons of butter, the vanilla and the salt. Press plastic wrap directly onto the surface and cool completely.
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Beat the softened cup of butter until light and fluffy, then gradually beat in the cooled custard until smooth. Both should be at room temperature.
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Preheat the oven to 350F and grease a 9x13 inch pan. Combine the cake mix, oil, 3 eggs and 1/2 cup milk until smooth, then fold in the cherry pie filling and chocolate chips gently so the cherries stay whole.
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Spread the batter evenly into the pan and bake 30 to 35 minutes, until a toothpick comes out with a few moist crumbs. Cool completely.
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Spread the German buttercream evenly over the cooled cake and refrigerate about 20 minutes to firm up.
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Place the chopped dark chocolate in a heatproof bowl. Heat the 1/3 cup cream until hot but not boiling, pour over the chocolate and let sit 2 to 3 minutes, then stir until smooth and glossy. Let it cool slightly.
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Pour the ganache over the chilled buttercream and spread evenly with an offset spatula. Decorate as desired and chill 20 to 30 minutes before slicing..
Note
Temper the eggs by whisking in a little hot milk before adding the rest, or they cook into visible curds; a fine sieve rescues a lumpy custard. Whisk constantly as the custard thickens, since cornstarch sets fast and catches on the pan. Press plastic wrap directly onto the custard surface so no skin forms. Both the butter and the cooled custard must be at room temperature or the buttercream splits; if it does, keep beating and it usually comes back. Fold the cherry filling rather than mixing it, so the cherries stay whole. Pull the cake with a few moist crumbs on the toothpick rather than clean. Chill the buttercream 20 minutes before the ganache, and let the ganache cool slightly first, or the layers blend. Better the next day. Keeps 5 days refrigerated or 3 months frozen in slices.