This Rainbow Loaf Cake is a bright and colourful pound cake, flavoured with vanilla and topped with whipped cream and sprinkles. It's so much fun and sure to brighten anyone's day! Make sure to use professional food colouring for the best and brightest results. I've used sweetened whipped cream for the topping, but you can top it with buttercream if you prefer. It can also be decorated with anything from fresh fruit to edible flowers as it's so versatile.

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Ingredient Tips & Equipment Information

Make sure all your ingredients (particularly the butter and eggs) are at room temperature before you start baking.
For the cake I used a baking spread, but you can use butter too.
You will need to use a professional grade food colouring to get the same bright colours that you can see in my photos. Brands I recommend are Colour Mill, Rainbow Dust Pro Gel and Sugarflair.
You can top the loaf cake with a vanilla buttercream if you prefer. Check out my Vanilla Loaf Cake for a vanilla buttercream recipe.
You will need a 2lb loaf tin for this recipe (you can test the size of your loaf tin by seeing how much water the tin can hold, 2lb will hold about 2 pints/1100ml of water). If you have a 1lb loaf tin, simply halve the ingredient amounts.
For easy lining of the tin, use a loaf cake tin liner.
Although I provide cup measurements, I highly recommend weighing your ingredients out using digital kitchen scales. It is the most accurate way to measure ingredients and will ensure the best results. Digital scales are very low cost and can be purchased for around £12 ($16.50).
For teaspoon (tsp) and tablespoon (tbsp) measurements, please use measuring spoons and not the type of spoons you eat with. Again this will ensure accuracy and provide the best results.

For the full recipe with measurements, head to the recipe card at the end of this post.

How to make Rainbow Loaf Cake

To make the cake, mix together the butter (or baking spread) and caster sugar, then whisk in the eggs and vanilla extract. Then add the self raising flour and fold in gently.

Divide the cake batter between 6 bowls, then colour them each a different colour of the rainbow using food colouring.

Add the batter into the lined loaf tin a spoonful at a time, alternating the colours. Give the mixture a swirl with a knife, then bake it for 1 hour or until a thin skewer inserted in the centre comes out clean. Leave to cool fully. Decorate with the sweetened whipped cream and sprinkles.

For the full recipe with measurements, head to the recipe card at the end of this post.

What is the best food colouring to use?

To get bright shades that remains strong after the cake is baked you need to use a professional grade gel food colouring. You can buy these easily from many online shops, like Amazon. I used the brand Sugarflair for this cake, other good brands include Rainbow Dust Pro Gel, Colour Mill and Americolor.

Do you have to top the cake with whipped cream?

I'm a huge whipped cream fan and I loved the idea of clouds of cream on top of the Rainbow Loaf Cake, however if you prefer buttercream you can find a vanilla buttercream recipe via my Vanilla Loaf Cake.

How long does the loaf cake last for and can it be frozen?

The loaf cake will last for 3-4 days in an airtight container in a cool place. If you have added the whipped cream, store it in the fridge. To freeze the cake (I don't recommend freezing the whipped cream topping), wrap the cake well in cling film or put it in an airtight container. You can also freeze it in slices, put a little baking paper between each slice to stop them from sticking together. Freeze for up to 3 months.

Can you make this loaf cake with plain/all purpose flour?

Self raising flour, which is very commonly used in the UK where I am based, already contains a raising agent and a little salt too. Therefore if you want to swap it for plain or all purpose flour, you will need to add some additional baking powder and also a little salt if you like. Some people like to add salt to cake recipes and some don't, so I'll leave that up to you as it won't affect the bake. The general advice is to add 2 teaspoons baking powder (a measuring teaspoon, not the kind you stir your coffee with) per every 200g plain or all purpose flour. So for this recipe you'd need to add 2 teaspoons baking powder. Please note, I have not tested this recipe using plain or all purpose flour.

Can this loaf cake be made gluten or dairy free?

Yes! For gluten free you can replace the self raising flour with a gluten free self raising flour blend. If you only have a gluten free plain flour blend, you will need to add baking powder. The general advice is to add 2 tsp baking powder per 200g flour, so for this recipe you'd need to add 2 teaspoons baking powder (a measuring teaspoon, not the kind you stir your coffee with). You may also like to add ¼ tsp xanthan gum for better texture. For a dairy free version, use a dairy free baking spread for the cake and a dairy free double cream for the topping. Please do check the labels of everything you use if serving to someone with an allergy or intolerance.

Can this cake be made into cupcakes?

If you'd like to make cupcakes, check out my Rainbow Cupcakes recipe for the details.

What size tin do you need for this recipe?

You will need a 2lb loaf tin for this recipe (you can test the size of your loaf tin by seeing how much water the tin can hold, 2lb will hold about 2 pints/1100mls of water). If you have a 1lb loaf tin, simply halve the ingredient amounts. I have a few different 2lb loaf tins, that all have slightly different measurements. The one I used for this recipe has internal measurements of 22cm x 11cm x 6cm. If your 2lb loaf tin is slightly narrower, your cake may need slightly longer to bake.

What is the best way to line a loaf tin?

For easy and quick lining of the tin, use a loaf cake tin liner, however if you don't have any of these you can use baking paper instead. Cut two pieces of baking paper, one wider piece and one longer and thinner piece. The wider piece will cover the two longer sides of the tin and the base, then place the longer thinner piece over the top of the first piece and cover the base again, and the smaller sides. Making a cross shape with the baking paper. I always grease the tin lightly before adding the liner or baking paper, as this helps to keep the paper in place and stop it from moving around when you add the batter.

Do you need an electric mixer to make this recipe?

While you can absolutely make this recipe with a wooden spoon and some elbow grease, I do recommend using an electric mixer for the best results. The cake will be lighter and fluffier when made with an electric mixer. You don't have to use an expensive stand mixer either, you can get electric hand whisks for as little as £10!

Should a loaf cake have a crack on top?

Yes! A slight crack down the middle of a loaf cake is totally normal. Some people even encourage a crack to happen by adding a line of melted butter or oil down the centre of the batter! If your loaf cake has a very large crack, it could be that it was baked on too high a temperature (or that your oven runs hotter inside than the dial says).

More tips for making the Rainbow Loaf Cake:

I used some rainbow sprinkles to decorate the cake. You can use any sprinkles you like, some fresh fruit or leave it plain.
It's really important to use good quality vanilla extract or paste for the perfect natural vanilla flavour. Avoid using essence as it's a synthetic flavour and personally I don't think it tastes as good.

Troubleshooting

My number one tip for getting the best results is to read through this whole page of tips and recommendations before starting, and follow the recipe exactly. If you have any questions about this recipe, or if something went wrong and you need help, please use the comment form below and I will get back to you. You can also get in touch with me on my Twitter, Instagram or Facebook. I'd love to hear from you!

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