Banana Layer Cake: Step by Step

Banana Layer CakeProducing this cake is a labour of (dessert) love. There are seven separate recipes to make, specialty ingredients and tools to acquire, and a significant amount of time to invest. Even though the end result was one of the tastiest cakes I (or my guests) have ever had, it falls into the “over-the-top” category for a home project. It's as labour-intensive as any of the Pierre Hermé cakes I've made in the past.

At a large restaurant, where you have the luxury of having someone make big batches of sauces, garnishes, and other staple ingredients, it's easy to make something that calls for "3 tbsp. of Fudge Sauce", but at home, you have to make that fudge sauce just to make the cake. There were several components that depended on having other ingredients pre-made, for example, the crunch required making a brittle first.

Unfortunately, there aren't any copies of the recipe online that use metric weights: the recipe on uses Imperial volumes and also substitutes a ready-made hot fudge sauce and crisped rice cereal for the feuilletine. Lame.

Seeing that the banana cake recipe calls for ½ batches of several components, I decided to make two 6-inch cakes. Here are my schedule and notes:

Sunday night

Banana Cream (One batch)

Banana CreamBanana Cream I cut all the sugar quantities by ¼. Most of the work is done in a blender, so it's quick to come together. When heating the mixture, don't worry about lumps you scrape up that look like scrambled eggs: just keep stirring. Sweetening whipped cream with icing sugar makes it taste chalky. But in the finished cream, it's not noticeable. Although Tosi strongly recommends it, I did not add yellow food colouring: my banana cream looked fine without it. I stored the cream in the fridge.

Banana Cake (Double batch)

Banana CakeBanana CakeThe recipe doesn't say what to do with the bananas for the cake, so I cut them into big chunks before incorporating them. I also cut the sugar in this recipe by ¼. The finished batter looks a bit like buttercream: mine looked properly emulsified, but barely. I baked this for a few minutes longer than specified, because it didn't brown at the minimum time. The finished cake is very moist, and stuck to the Silpat, so be careful when removing it. I double wrapped this in plastic film and stored it, still in the pan, in the fridge.

Monday night

Hazelnut Brittle (one batch)

Hazelnut BrittleHazelnut BrittleMaking a dry caramel is trickier than a wet one. I was busy doing something else, and the sugar at the edges of the pot turned golden before I started to mix in the unmelted sugar. As a result, there was still plenty of unmelted crystals even though the overall colour of the mixture was golden. I kept heating and stirring until the mixture was no longer cloudy. Because the yield is so small, the melted mass of sugar starts to cool and harden as soon as the nuts are added, and when it hits the sheet pan. You need to work quickly to spread it thinly! It's not the end of the world if you have a thick brittle: it just means a bit more work to break it up before pulverizing it in the food processor. I stored this at room temperature in an airtight jar.

Hazelnut Crunch (double batch)

Hazelnut CrunchHazelnut CrunchOnce all the ingredients are ready, making the crunch is just paddling all the ingredients together. I couldn't get a good quality hazelnut paste, so I substituted hazelnut butter, which has no added sugar. Try to get feuilletine, as called for in the recipe. It has a wonderful texture that isn't replicated by frosted corn flakes or crisped rice cereal as used in some adaptions of Tosi's cake. The hazelnut crunch is irresistibly delicious; I couldn't stop eating it. I stored this in a container at room temperature.

Tuesday night

Fudge Sauce (one batch)

The cream/glucose mixture resembled glue paste, not very appetizing. Next time, I would sift the cocoa powder before adding it, as there were lumps in the sauce that were hard to stir out. Actually, there won't be a next time (see notes at the end).

Chocolate Ganache (two batches, made separately)

Chocolate Hazelnut GanacheChocolate Hazelnut GanacheBecause such a small quantity of ganache sets quickly, I made one batch at a time, intending to have it ready just before cake assembly. It does need a little bit of time to thicken, or else it's too runny to stay on the cake.

Hazelnut Frosting (double batch)

How can you beat two tablespoons of butter in a hand mixer!? A double recipe was still a very small quantity and required lots of scraping to ensure everything was thoroughly combined. It's interesting that Tosi calls for kosher salt in her recipes. In this fat-rich frosting, the only water to dissolve the salt comes from the butter. So most of the crystals stay whole, and you taste mini hits of salt flavour.

Assembly of first cake

Assembling the Banana Layer Cake I only have a large 7¾" cake ring, so I used a 6" springform band instead. Its edge is too thick to use as a cutter, so I used a paring knife and the band as a guide to cut out two cake circles. The cake layers were damp and stuck to the Silpat, but made it into the ring without crumbling. I didn't use that much milk to moisten the cake layers, they seemed wet enough. Spreading the thickened ganache was a bit tricky, so don't let it set too much. Also, make sure that the acetate strips overlap, especially the one used on the top. Once assembled, I put the cake into the freezer.

Wednesday night

Assembly of second cake

I took the first assembled cake out of the freezer and prepared it for storage. The springform band was actually helpful, as I could undo the buckle and lift the band off the cake. I double-wrapped it in plastic film, and returned it to cold storage.

To make the second cake, the only components that needed warming up were the fudge sauce and frosting. The microwave took care of the former, and 30 minutes on the counter took care of the latter. Re-using the two acetate strips to make the second cake wasn't a problem. Assembly was a bit faster this time, as I knew

Saturday and Sunday nights

Banana Layer Cake: SliceWe were hosting people for dinner on both nights on the weekend, and I had a feeling that this 6-inch cake would be enough to feed 8 people (+3 kids). I was right. The slices of this dessert (my son kept calling it “tall cake”) were enormous, and a small wedge was all we required. We all loved the combination of flavours, and I especially enjoyed the textures: creamy, melty, crunchy!

Would I make this again? Sure, but only for a special occasion! Here are some notes for future me to refer to:
  • Skip making the fudge sauce, and omit it as a component of the ganache. That's one less thing to make, and simplifies another recipe.
  • Reduce density and moistness in the cake to make it lighter. Maybe by using cake flour and incorporating less liquid.
  • Reducing the sugar in the various components didn't have a noticeable impact on the overall taste or texture, in my opinion.

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