Before I get down to the recipe, a little background. This MilkBar cake was designed for a customer’s son. When I customise a cake for someone, I find out what that person’s favourite desserts and fruits, and usually from the answer I can roughly tell the customer’s preferred flavour palate. In this case, he liked peanut butter, caramel, chocolate, salt and bananas. As he was a teenager, I wanted to keep it simple. So I proposed a Valrhona chocolate buttermilk cake with salted peanut butter buttercream. Two sponges sandwiching a layer of peanut butter buttercream and Valrhona crunchy chocolate pearls.
After much thought, I decided that this cake recipe should be divided into 2 parts because by separating the sponge itself from the buttercream, I can explain in greater detail the rationale of what makes the cake good. After all, the basis of a good cake is the science behind it. Do note that everything formulated by me is through empirical knowledge.
The general philosophy of what baking a cake is (to me): the emulsion of fats and water (liquids). It’s the gentle balance between both of them. So that’s why when you over add fluids, you will see the cake batter split (break). It can happen from even adding eggs that are too big. When that happens though, most recipes will tell you to add in flour. It only helps to hide the split but it actually doesn’t solve it. Instead it actually makes the cake more dense.
A couple of things to take note. Milk is an emulsion of water and milk fats. Egg whites are made of proteins and water. When to use baking powder or baking soda? Baking soda for me when there is a presence of acids (like in buttermilk, yoghurt). In most cases for a chocolate cake, they will use cocoa powder. I find that it dries the cake. Instead, using chocolate and melting it down, is a lot more work and trickier but gives you a better flavour.
When melting chocolate be careful because melting chocolate is sensitive to water. Just a tiny drop of water is what it takes to cause a chocolate seizure. Why? Chocolate is a dispersion (opposite of an emulsion), consisting of solids distributed in a fatty (continuous) phase. It contains miniscule cocoa particles (mean diameter ca. 0.016 mm) and sugar particles too small for our tongue to notice them as grainy when properly distributed. The sugar is hydrophilic (water loving), and repelled by the fat. An important function of the lecithin emulsifier is to build protecting layers around the sugar particles so that they don’t separate from the fatty phase and give a grainy texture. The emulsifier is commonly lecithin (lecithin is also a natural constituent of egg yolk, and the main reason for why the yolk doesn’t split into a fatty and a watery phase).
In the case of this cake, after adding 4 eggs, you will see the batter split, adding the chocolate, it will act as the binder and bring the cake batter back together.
Also I check my cake whether it is ready by catching a whiff of the cake, then using my fingers to press the centre of the cake (it should bounce back) and come away from the cake tin sides slightly.
Chocolate Buttermilk Cake (adapted from “More from Magnolia”)
makes 1 big cake in 2 or 3 layers, or 24 cupcakes.
Oven setting: for 8” layers 140degC, cupcakes 150degC. Use fan forced setting.
170g of Valrhona chocolate couverture (I like mine at least 60% Cocoa)
200g of unsalted President Butter (soften, check by stabbing it with a knife, it should go through easily. The butter should also not be melting)
1 cup of brown sugar
½ cup of white caster sugar
4 eggs ( I use 55g eggs)
2 cups of plain (all purpose) flour
1 tsp of baking soda (always make sure they are not more than 6 months old)
1 cup of cultured buttermilk (room temperature)
½ tsp of vanilla extract (my favourite is Nielsen-Massey or real deal vanilla extract)
- Using a pot of boiling water, put a bowl over and melt the chocolate couverture. Make sure the water isn’t touching the base of the bowl. Then keep stirring until the chocolate melts. Leave aside to cool to room temperature.
- Sieve the flour and baking soda together. Then using a whisk, whisk the flour. This is to introduce more air into the cake. (By the way if you don’t own a sieve, you can just whisk the flour as well.
- Use a stand mixer with a paddle attachment or hand mixer with beater attachments to beat the soften butter. Then add both brown and white sugar in parts to the whipped butter and keep mixing them until you see that the sugar crystals in the mixture has become very fine and the mixture has also become fluffier and paler.
- Using a spatula, scrape the sides of the bowl. Always try to scrape the bowl after every addition to ensure even mixing.
- Add eggs one at a time and using a mixer (hand/stand), mix before every additional egg. (Add egg, mix, scrape, repeat)
- Pour the 1 tsp of vanilla extract in. Mix till incorporated.
- Add in melted chocolate. Mix.
- Add in 1/3 of flour, mix lightly till you don’t see the flour bits, then add in ½ of buttermilk, mix. Repeat till you finish both buttermilk and flour.
- Grease and flour cake tins (if you are using that) or line 24 cupcake moulds with paper. Put in the middle of the oven. Bake.
Have fun baking! I absolutely love the beautiful soft crumbs that this recipe gives. This is a very moist and soft chocolate cake. Very delicious.