Apple and Blueberry Crumble Cake

Today I have an extra special recipe, because I’m featuring Sarah as a guest writer! On Twitter, I love following Sarah for her delicious-sounding desserts and stunning cakes. I was so excited when she offered to do a post here, and immediately we decided on featuring one of those gorgeous cakes. Enjoy getting to know Sarah and this recipe, and please, drool over the photos of this apple and blueberry crumble cake.

Note that Sarah is based in the UK, so she may use some measurements and terms that are less familiar around here! However, I tried to add in notes about imperial measurements and substitutions where needed.

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What You Need to Get Started

• Pantry: Light brown sugar, Self-rising flour, Baking powder, All-purpose flour, Oats, Brown sugar, Powdered sugar
• Fridge: Butter, Eggs, Milk
• Produce: Blueberries, Apples
• Spice Cabinet: Cinnamon
• Equipment: 8-inch cake pans, Parchment paper, Mixing bowls, Whisk, Silicone spatula, Cooling rack
• Optional Equipment: Stand mixer or hand mixer; If you’d like to follow Sarah’s weight-based measurements to get the exact cake pictured here, you will want a kitchen scale, as well.

Now, let’s hear from Sarah!

About This Cake

This apple and blueberry crumble cake is the perfect dessert after a busy day. A soft and moist blueberry and apple sponge, cinnamon buttercream and decorated with crumble and more blueberries.

I decided to make this apple and blueberry crumble cake two layers. Normally I make cakes slightly larger just because I like large cakes like my Cookie Dough Showstopper Cake and my Rainbow Drip Cake but I am so glad I didn’t with this cake as I think it looks great with just two layers.

I did make the apple and blueberry crumble cake layers slightly larger than I would have if I was making a three-layer cake but I think they look utterly delicious. To make this cake I used 300g of the main ingredients so sugar (1.5 cups), butter (1 1/3 cups), and flour (2 3/8 cups). I then used 6 large eggs, I normally follow the rule that for every 50g (1/3 cup) of flour you have you use 1 large egg.

In this recipe, I also used Light Brown Sugar instead of Caster Sugar (superfine sugar). This is completely up to you. I used light brown sugar as it gives the cake a more toffee flavour which is delicious with the fruit, cinnamon buttercream and crumble topping. If you would prefer to use caster sugar, then that is absolutely fine; the cake will still taste delicious. You could also use a combination of both sugars too if you would prefer, for example, 150g (3/4 cups) of each.

How to Make Apple & Blueberry Cake

I mixed the butter and sugar together for a few minutes until it was soft and lighter in colour. I added in the flour, baking powder and eggs and mixed again. Next, I peeled and roughly cut my apples into 1cm (2/5 inch) cubes. I did this now because when you peel and cut apples and leave them to the side they tend to start going brown pretty quick. I added the apples and blueberries into my cake mix and folded them in with a spatula as I wanted the blueberries to stay whole.

Folding is slightly different to mixing. When you are folding a mixture you want to be gentle so as not to lose any of the air from the mixture. I use my spatula and go around the sides of the bowl pushing the mixture inwards and then cut through the middle of the bowl.

Divide the apple and blueberry cake mixture into the cake tins and bake in the oven for 35-40 minutes or until they are golden brown and spring back when touched.

How Do I Know When The Cakes Are Ready?

I wouldn’t recommend inserting a skewer into the centre of the cakes as if you hit a piece of apple or blueberry then this will show on the skewer and make it look as though the cake is not done. 

You can also listen to your cakes when you remove them from the oven. If they are still bubbling and crackling then they are not done. You will know they are done as they will be silent when you remove them from the oven.

How to Make the Crumble & Frosting

Crumble

While I was waiting on my apple and blueberry crumble cakes to cool I made the crumble. To make this I added the oats, flour, brown sugar and butter. I rubbed it between my fingers until it begun to clump together. I then poured this onto my baking tray and baked in the oven.

Buttercream

To make the buttercream for your apple and blueberry crumble cake I mixed the butter and icing sugar together until it was lovely and soft. I then added in ¼ teaspoon of cinnamon. I am not a massive fan of cinnamon so I didn’t want a super strong flavour. 

If you would prefer a stronger cinnamon flavour then I would add ¼ teaspoon of cinnamon at a time mixing after each addition until you reach the flavour you would like.

I piped the buttercream onto the bottom layer of the cake first and then added the crumble and blueberries. I didn’t use apples in the decoration because I thought they would go brown pretty quick.

Then I added the second cake on top and decorated it with buttercream, crumble and of course some blueberries. If you didn’t want to use fresh blueberries you could use blueberry jam or coulis instead.

Specific Ingredients

• Self-Raising Flour – I used a supermarket brand. In this recipe I use both self-raising and plain flour and I often get asked questions regarding the difference between both flours. Plain flour is just regular flour, self-raising flour is plain flour but it includes baking powder or another rising agent. You may come across some recipes that call for self-raising flour and no baking powder and that is because there is already baking powder included in the flour. I used baking powder to give the cake some extra rise because they are quite large cakes.

• Light Brown Sugar – I used Billingtons
• Baking Powder – I used Dr Oetker
• Unsalted Butter – For the cake you can use either unsalted butter or a baking spread like Stork (margarine). In the buttercream however, you must use unsalted butter. If you use a baking spread it will just make the buttercream far too soft and runny.
• Icing Sugar (powdered or confectioner’s sugar) – I used Silver Spoon
• Oats – I used Quaker oats
• Plain Flour – I used a supermarket own brand

Special Equipment

• Spatula – I will always use a spatula over a wooden spoon. Spatulas will be able to get any left-over batter from around the sides of the bowl.
• Scales – If you don’t use scales to weigh your ingredients you are essentially setting yourself up to fail. So many things can go wrong if you use too much flour or sugar in recipes.
• Baking Trays – I used flat baking trays for my crumble.
• 8” Cake Tins – I use these 8” cake tins (not available in US, here’s something similar). I find they make the perfect sized cake. If you use larger cake tins you will find that your cake is thinner and will take less time to bake than mine and if you use smaller cake tins you will find that your cake is thicker and may take longer to bake.
• Piping Tips – I used a Wilton 1M Piping Tip
• Piping Bags – I use these large savoy piping bags (not available in US, here’s something similar).