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A surprise cake with a wow effect when you cut it! The surprise cake with a hidden rainbow for a delicious and colorful surprise effect for the minis - a surprising rainbow cake!
Rainbows are just beautiful! We love them – in the sky and especially on our cake plate! Whether as brightly colored rainbow muffins, as Rainbow cookies from the roll or Cake pops decorated with a fondant rainbow – we can’t get enough of rainbows!
Today the kids and I are baking a rainbow cake! But not just any cake, but a rainbow cake with a hidden rainbow. A rainbow incognito, so to speak 😉

Chocolate children's birthday invitation
With our children's birthday banderoles for Ritter Sport Minis you can create a unique invitation for your child's birthday!
A lovingly designed banderole (if necessary with a preconceived invitation text) for parents with little time!
Recipe for our hidden rainbow cake
Today we're turning a juicy yogurt bundt cake into a rainbow cake. The sponge cake is a very easy all-in recipe. When coloring the dough for the rainbow, your kids get to know color theory in a fun way and can mix colors vigorously.

Ingredients
Sponge dough
- 200 g margarine
- 200 g sugar
- 1 packet of vanilla sugar (15g)
- 1 tsp tonka bean
- 5 eggs
- 250 g yogurt (we used 250 g Skyr vanilla)
- 350 g (spelled) flour
- 2-3 tbsp milk
- 1/2 packet of baking powder (7 g)
- Food coloring in all colors of the rainbow* (we used red, pink, yellow, green, blue and purple from the GoodBake drip tray)
Discount code for your purchase at GoodBake: With the discount code “LIA12” you save 12% on your purchase from Goodbake.
Icing
- 50g powdered sugar
- 2-3 tbsp lemon juice
- Colorful sugar sprinkles*
Baking accessories
Kitchen scales, mixing bowl, hand mixer, 6 small bowls, teaspoon, tablespoon, dough scraper, Bundt cake tin (I used the “Raggio” baking tin), cooling rack
Preparation
In the first step we make a light dough for our yoghurt gugelhupf.
- First, the margarine is stirred until creamy using a mixer/hand mixer.
- Add the sugar, vanilla sugar and tonka beans and mix until the sugar is dissolved.
- Add eggs one at a time and mix well.
- Then add the yogurt.
- Finally, add flour and baking powder to the batter and mix everything into a smooth batter. If the dough is still too firm, add a little more milk.
- Now the oven is preheated to 175°C top/bottom heat.
Next we turn our attention to the hidden rainbow.
- To make the hidden rainbow, divide a third of the dough into six small bowls (approx. 2-3 tablespoons of dough per bowl) and use your minis to color each one in a different rainbow color. We used the colors red, pink, yellow, green, blue and purple.
Now fill the dough into the greased Bundt cake tin. (If you bake with a silicone baking pan, follow the instructions for use of the silicone baking pan - most of the time they will not be greased! Here you can find my 5 tips for success when baking with silicone baking molds)
- First, put half of the uncolored dough into the Bundt cake pan and use a spoon to pull the dough up the edge of the baking pan. So that the edge of the mold is “coated” with dough and a hollow for a hidden rainbow is created (see picture).
- This hollow is now filled one after the other with the colorfully colored dough. The colorful dough colors are layered on top of each other in the cavity (see pictures). You should make sure that the colorful dough is only distributed in the dough cavity, as the rainbow does not remain “hidden” if the colorful dough runs all the way to the edge of the baking pan.
- After all the colors have been layered in the cavity (we chose the following order: red, pink, yellow, green, blue, purple), carefully cover the colored dough with the remaining light, uncolored dough. Make sure that you carefully spread the light dough over the colored dough so that the colored dough is not pressed against the edge of the baking pan.
- The rainbow cake-to-be is then baked in the oven for 50-60 minutes at 175°C top/bottom heat. Since the baking time depends on both your baking pan and your oven, do the chopstick test to test whether your rainbow cake is baked through.
- When the rainbow cake is baked, let it cool down in the baking tin for 10 minutes and then turn it out of the tin and let it cool on the cake rack. (Attention: If you bake in a silicone baking mold, let the cake cool in the mold, as you can read in my blog post 5 tips for success when baking with silicone baking molds 😉)
- Finally, decorate the rainbow cake as desired. We mixed icing from the powdered sugar and lemon juice and spread it on our Bundt cake. And of course then decorated with colorful sugar sprinkles.
And the rainbow cake is ready to surprise you!
Preparation in pictures









Cutting this rainbow is an absolute highlight and super exciting! Even if you baked it yourself, you won't know what the hidden rainbow turned out until you cut the rainbow cake! A real, little moment of tension!
For those who are not involved in the baking process, there will be a colorful, pretty surprise when you cut the rainbow cake! I love it!
My kids & I wish you a lot of fun baking and even more fun cutting this pretty surprise cake!
Yours, Lia
Have you baked the recipe?
How exciting! We're really happy about that! We are pleased that we were able to delight you with our recipe. Feel free to share your treat with us on Instagram using the hashtag #backenmitminis.
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