I made this surprise rainbow bundt for my Grandma last week, she actually requested a simple vanilla sponge cake but with having a grandchild that’s as extra as me she wasn’t surprised by what she got 😂.

Grandma thought it was beautiful and so delicious and moist. She has not been herself lately, with the dementia slowly deteriorating she feels lost and unlike herself. Hence the rainbow cake, I knew it would cheer her up and I’m so glad I left her with a smile on her face.

She requested cookies this week (with the help of my son 🤣 ofcourse) so that’s this weeks baking project sorted.Here is a step by step on how you can make this surprise rainbow cake.

Hope you enjoy it and it brings a smile to anyone you serve it too ❤.

Surprise Rainbow Bundt Cake


1/2 cup unsalted butter softened to room temperature

1/2 cup canola oil1

1/2 cup sugar

4 eggs, room temperature

1 Tablespoon vanilla extract

3 cups cake flour

1 Tablespoon baking powder

1/2 teaspoon salt

1 1/4 cup buttermilk room temperature

Gel food colouring in red, yellow, green, blue, purple

Pink chocolate ganache

120 g good quality white chocolate

Pink colouring powder (using liquid colouring will seize your chocolate)

240 ml cream


1. Preheat oven to 177C and prepare bundt pan by spraying with baking spray. Set aside.

2. In the bowl of a stand mixer cream together the butter, oil and sugar until creamy and well-combined. Add eggs, one at a time, beating well after each addition.

3. Stir in vanilla extract. In a separate, medium-sized bowl, whisk together flour, baking powder, and salt.

4. Using a spatula and gently hand-mixing, alternate adding flour mixture and buttermilk to the butter mixture, starting and ending with flour mixture and mixing until just combined after each addition. The batter should be smooth and completely combined.

5. In 5 separate bowls, add 5 tablespoons of batter in each. Using gel food coloring add red, yellow, green, blue and purple to each bowl and stir to combine the colors. Use about 2/3rds of the remaining batter to fill your bundt pan. Leave the last third for the top, to cover the rainbow.

6. Begin by filling your piping bag with red and make a circle within the bundt on top of the white batter. Make the border of the circle pretty thick by circling several times – you are going to be making 4 more circles with thinner borders within it. Use the back of a teaspoon to smooth out the red batter and even it out in preparation for the yellow.

7. Do the same with the yellow, leaving a slight space on either side so the red is still visible. Continue with the green and so on, until you have a thin line of purple.

8. Use a spoon to gently add the rest of the white cake batter on top. Smooth top over with a spatula or the back of a spoon.

9. Evenly divide batter into your prepared cake pans, and bake on 175C° for 30-35 minutes or until a wooden skewer comes out clean.Allow cakes to cool in their cake pans for 10-15 minutes before inverting onto cooling rack to cool completely before topping with ganache.

Pink chocolate ganache

Place chopped chocolate in a medium heat-proof bowl. Heat the cream in a small saucepan over medium heat until it begins to gently simmer. Pour over chocolate, then let it sit for 2-3 minutes to gently soften the chocolate. Slowly stir until completely combined and chocolate has melted. The finer you chopped the chocolate, the quicker it will melt with the cream.

I like letting my ganache sit at room temperature to cool and thicken. It will fully cool within 2 hours, mix in food colouring powder and drizzle over your bundt, add sprinkles and serve.

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