How to Make Tropical Juice Sourdough Cake

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This sweet Sourdough Discard Cake is flavoured with concentrated Tropical juice. It is a delicately flavoured cake, with a moist texture. This cake was born because of a disgustingly sweet bottle of tropical juice which was undrinkable. Condensed, and turned into a cake, was the best thing we could do! This is a large cake and is easy to transform into an impressive layered dessert.

Ingredients in Sourdough Tropical Juice Cake

This cake is made from normal, everyday ingredients. It is an inexpensive cake to make, and you probably won’t have to go out and buy anything special for it.

• White or oat flour – if you are worried about eating highly processed white flour, you can ferment the cake batter for 7 hours to improve the nutritional profile of the cake. Or, you can blend up oats and use them, instead. If using oats, you do not need to worry about fermenting the cake batter, since they have a better nutrient profile than plain white flour. But hats off to you, if you do! Simply replace the quantity of flour 1:1 for ground oats.
• Concentrated Tropical Juice – you could use tropical juice or any other kind of juice you have on hand. We mistakenly bought a disgusting version of tropical juice which was way too sweet to drink…hence this cake. The sweetness in the juice makes for a really lovely cake!
• Sourdough discard – a fermented cake needs sourdough discard to properly ferment. Whether you do this or not, the sourdough makes this cake a lovely texture, and this is a great recipe to use up your sourdough discard. I mean, a cake out of a by-product? How cool is the sourdough process?
• Oil – not only does this make the cake dairy free, but it means the cake is easier to mix and lasts longer, too! Because of the oil, it won’t dry out in the fridge and can be kept fresh in there.
• Truvia or sugar – if you do not have my favourite sweetener, Truvia, you can use any other quantity of granulated sweetener. Bear in mind that a cake this large needs about 2 cups of regular sugar. You can adjust the sweetener according to the packages directions. You only need 2/3 cup of Truvia for this cake, since it is three times as sweet as regular sugar.
• Salt – Do not leave it out! It makes the flavours in the cake sing!
• White or cider vinegar – the acidity of the vinegar is needed to activate the rising agents.
• Baking powder and baking soda – the main rising agents in this cake. This is a large cake, so do not doubt the quantity of these ingredients – you really do need that much!
• Almond or vanilla essence – almond essence is quite strong, so only use it if you really like the flavour. As a default, I slosh in the vanilla essence like there’s no tomorrow!

How to Make Sourdough Tropical Juice Cake

You can either bake straight away or mix the batter in advance and give it 7 hours to rest and ferment. If you are using oat flour, there is no need to ferment the batter.

The Night Before:

To make the pre-ferment, mix the flour, oil, starter, and water in a bowl. Cover, and leave to prove overnight (or a minimum of 7 hours).

You can add the Tropical Juice concentrate at any point during the 7 hours. It is probably best to add it right at the end, so that the heat from the boiled juice can dissolve the pre-fermented dough and make it easier to incorporate.

To make the Tropical juice concentrate, simply pour 2 cups (or more) of juice into a pot, and simmer over a medium heat until the juice has reduced to one cup of liquid. Note, if you add more juice, it will take longer to get it to that one cup measure, but the flavour will be deeper. So, if you have lots of juice to use up, I would recommend doing this!

Give yourself an hour to get the juice to the right quantity. I would start it after the batter has been fermenting for 6 or 6.5 hours.

Once you have one cup of tropical juice, add it, hot, to the pre ferment mixture.

Get Ready to Bake

Now you can add the remaining ingredients and bake the cake.

When you are ready to bake, you should preheat the oven to 160 degrees Celsius. It needs to be warm by the time you pop the cake in.

Line a 22cm loose-bottomed cake tin with baking paper.

To the pre-ferment mixture, add the remaining ingredients. Be sure not to over-mix, because this disrupts the carbonation process (aka: ruins the fluffy texture).

Pour into the prepared cake tin, and place in the centre rack of the oven. Bake for 75 minutes, or until a skewer inserted into the middle comes out clean.

Frosting Ideas

This recipe makes a really large cake which stacks impressively with delicious icing.

Me, I strongly believe that icing can make or break a cake. In my mind, it’s got to be thick, luscious, leave-your-teeth-marks-in-it delicious. It needs to be sweet, and for a white, lightly fruity cake, it needs to be a little bit tart.

I have made many different frostings. For my Sourdough Carrot Cake, I made a Passionfruit Frosting, which would be sublime on this cake. For my spiced Zucchini Cake, I made a simple Vanilla Frosting. Atop my Sourdough Apple Cake, was a lightly spiced frosting.

While all three of these flavours would work well with this Sourdough Tropical Juice Cake, I wanted to try out a different flavour (just because!).

I made the Coconut Butter, as I usually do, but instead of using 2 tins of coconut cream, I subbed in some leftover Tropical juice for one tin of coconut cream.

Friends, the flavour was delicious! Subtly Tropical, subtly sweet, and really drew out the tropical flavours in the cake. To add a bit of zing, I spread a thick layer of sugar-free apricot jam before I piped the icing on.

Game-changer! It was absolutely incredible. It gave the flavour punch that this cake really needed.

How to make this Sourdough Tropical Juice Cake really good

Get the Tropical Juice bit right

The Tropical juice is where the signature flavour of the cake comes from, so concentrating the juice is key. Reducing the tropical juice deepens the flavour and sweetness for the cake. You do not need to use tropical juice. You could use any kind of juice you have on hand. The juice I used was quite thin, so if you have a pulpier juice on hand, such as Feijoa or orange juice, you may not need to concentrate the liquid. If the juice you have is cranberry, apple, or any other kind of transparent juice, then I would definitely concentrate it.

Time it right

I actually think it is so handy that I can pre-make the cake when I have a moment, to take the pressure off a bit later. You can make the cake all in one day if you get your act together early enough. If you start this batch in the early morning, you will be ready to bake in the late afternoon. My preference is to make the batter the night before. When I do this, I bake the cake mid-morning when I have a gap in the chores (7 hours fermentation time is just a minimum).

To ferment or not to ferment?

There is no need to ferment this cake batter – I just like doing it because it improves the digestibility of the cake. If you are pressed for time, the cake will be delicious even if you skip fermentation. Simply preheat the oven, mix, and bake.

Does the sourdough affect the flavour of the cake?

No, the sourdough discard and process of fermentation does not affect the flavour of the baked cake. The raw batter does not taste very nice, simply because it is sour from the sourdough discard and bitter from the baking soda. However, there is not a hint of this in the cooked cake. It is sweet, tropical and lovely to eat.

How long does this cake take to cook?

Baking times will vary depending from oven to oven. Keep an eye on the cake. It needs at least 1 hour, so check in every 10 minutes or so after that.

Is this cake suitable for those with sensitivities?

This cake is suitable for vegans and for those who have an intolerance to dairy and eggs. Since it is fermented for 7 hours, it is easier for those who have a gluten intolerance. It can be flour free if you use oat flour. It is nut free, and sugar free!