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Home • Recipe • Tray Bake • Polka Dot Slice
Published by Amy
Easy and delicious tray bake, made with rainbow chocolate drops, coconut and vanilla. A family favourite but particularly loved by kids!
Whenever I’m looking for inspiration for recipes, I go straight to my collection of old recipes books. Some from Granny (although those are very much on loan!) but most from Great-Granny. Some are proper publications, some are binders filled with recipes from magazines & newspapers, but many are little DIY books, made by groups who wanted to raise some money for whatever their cause. These are undoubtedly my favourite recipe “books”.
I first came across Polka Dot Slice in one of these lovingly made books, and I instantly knew it would be a hit with my kids. Anything containing some Smarties or M&Ms is guaranteed to please two little boys! It’s why our Rainbow Cookies are always a highly requested bake at home.
As expected, the kids loved Polka Dot Slice! A lovely little tray bake cake, made with coconut, vanilla and chocolate rainbow drops. What’s not to love?
The texture is less “light & fluffy cake”, and more “perfect amount of bite with sweet delicious flavours”, thanks to the desiccated coconut adding an extra dimension of texture, not to mention taste.
As is often the case in recipes inspired by the ones that I find in these little old cook books, I’ve played around with the various elements of this sweet rainbow cake traybake to get everything just-right. My favourite addition? That sprinkling of sugar on the top, which finishes it off beautifully and adds just a little crunch too.
Margarine or ButterMy personal preference is to use a margarine due to it being easier to cream with the sugar. However butter is perfectly fine to use too, if you wish. Just ben sure your margarine or butter is softened first, to make the creaming easier.
Caster SugarPolka Dot Slice is a cake tray bake, so we start with a cake-like ingredient base. Caster sugar is preferable because of this. You could swap out for a golden caster sugar, if you want aa slightly less-sweet option, or a more caramel-y flavour.
Free-range EggsAgain, this is a cake tray bake, so the usual cake base of butter/margarine, sugar, eggs and flour applies. It isn’t too crucial what size of eggs you use in Polka Dot Slice; just be sure to use free-range when possible.
MilkA little bit of liquid helps make this tray bake cake batter a little easier to work with, especially once you’ve added the coconut and flour. What kind of milk you use is up to you; dairy, soya, oat, coconut, almond…all should work fine in this recipe.
Vanilla ExtractI’ve specified vanilla extract as the vanilla of choice in this traybake but if you are feeling fancy you could swap it out for vanilla paste or a vanilla pod. Just avoid using a vanilla essence – the synthetic taste is never really comparable
Desiccated CoconutThe coconut not only adds another level of flavour to Polka Dot Slice, it also changes the texture from a classic sponge cake, to a slightly denser tray bake cake. Alongside the vanilla and the chocolate rainbow drops, the desiccated coconut becomes an underlying complimentary taste; as opposed to a full-on flavour at the forefront.
Smarties or M&MsEither is fine, it’s really a case of personal preference, or whichever you can get hold of easier. I usually opt for Smarties as they are easier to get hold of locally, but M&Ms do have a slightly brighter appearance.
Can I swap out the Smarties/M&Ms for something else?Sure, why not. It will obviously take away the rainbow polka dot finish but there’s no reason you can’t tailor the recipe to your personal taste. Some alternatives I think would work well could be chocolate chips, fudge chunks, chopped nuts or even dried fruits.
I don’t like coconut, what can I use instead?We love coconut and think it is a must-have in this recipe. However, a possbile alternative ingredient that may work is ground almonds. I haven’t tried and testsed this but it could be worth a shot if you really don’t like coconut and still want to give this recipe a try
• The recipe specifies you use approximately 80g of Smarties or M&Ms. The reason for this is because a tube of Smarties in the UK is usually 38g, and a bag of M&Ms 45g. I’ve tried to give an amount that will allow you to follow the recipe without having to buy unnecessary extras, or leave you short. You can of course use more or less to suit your taste, or to what you have readily available.
Nut-free: This recipe for Polka Dot Slice doesn’t contain any nuts (coconut isn’t a nut, despite the name) but be sure to double check each ingredient for any hidden allergens.
Dairy-free: To make your Polka Dot Slice dairy-free, simply use a dairy-free margarine, a dairy-free milk and Daisy & Dom D&Ds.
Tried this on my Grandchildren with ground almonds it was lovely They loved the smarties ! Gosh Granny you are clever , I took all the praise !! It’s simple but different and tasty Thank you
Thank you for the lovely feed back, Ruth. And I’m pleased to hear it was a success with Ground Almonds too!
Worked out perfectly and very nice for a change. Thank you
Used ground almonds and some white chocolate smarties left over from Christmas and only just in date, Big Big hit with my grandbabies, especially the autistic one who doesn’t like dark or milk chocolate, and is often left out of things with smarties in, so many ranks for this, it will become a regular for me.
So easy to make grandchildren loved it
Made these twice – completely free from and gluten free flour and with the ‘normal’ ingredients. both times they tasted delicious but both times the smarties on top sunk into the mixture – so no Polka Dot effect. my mixture looked as the video. it certainly didn’t effect the taste and th chocolate was a surprise as no evidence on top!!!
Delicious taste although the smarties sank to the bottom. Why do you think this happened. I will make them again. Many thanks
How well does this keep and/or freeze?
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