Rainbow Birthday Cake

IMG_2546One Easter weekend about 15 years ago, I made this cake.  I wasn’t sure who was going to eat it all, but I thought it would be fun for the family.  It was sitting on the kitchen table, uncut.  The dogs started barking, letting us know someone was arriving.

A huge black Shire horse was coming down the driveway pulling a farm wagon full of friends.  They’d harnessed her up for an Easter weekend outing, and ended up at our place.  With Queen standing patiently by, we shared the cake before she moved her dinner-plate sized hooves and took them all away, back up the hill.

This cake is so fun for birthdays (even for someone’s 55th last year).  Even though this is done in rainbow colours, there’s no reason why it couldn’t be done in gradients of someone’s favourite colour.  Have fun!Click here for printable version.

You’ll need three 9” round cake pans, and a selection of paste food colours.


1 c butter, softened

1¾ c sugar

4 eggs

2 t vanilla

2¾ all-purpose flour

2 t baking powder

¾ t baking soda

1¼ c buttermilk (or 1c + 3T milk with 1T lemon juice added)

Red, orange, yellow, green, blue and purple paste food colouring.  If you are using just red, yellow and blue to blend for your secondary colours, be sure to use just a tiny bit at a time until you get the correct blend.

Butter icing (follows)

Fluffy icing (follows)


Butter and flour three 9” round cake pans; line bottoms with parchment or waxed paper. Set aside.IMG_2458

In large bowl, beat the butter with the sugar until fluffy.IMG_2462

Beat in eggs, 1 at a time, scraping the sides of the bowl and beating well after each.

Beat in vanilla.

Whisk together flour, baking powder and baking soda.

Mix into butter mixture alternately with buttermilk, making 3 additions of flour mixture and 2 of buttermilk.IMG_2468





Divide among 3 bowls. With food colouring, tint 1 red, 1 yellow and 1 blue.



Scrape each into 1 of the prepared pans, smoothing top. Use a scale if you’re concerned about even distribution.IMG_2473

Bake in the center of a 350° oven for 30 minutes or until cake tester comes out clean. Let cool in pans on rack for 15 minutes.IMG_2486

Run knife around edges; turn out onto rack and peel off paper.

Turn right side up; let cool on rack.

Divide the Butter Icing among 3 bowls.

With food colouring, tint 1 orange, 1 green and 1 purple.IMG_2518

Place the red cake layer on flat serving plate; spread the top with the orange icing.

Place the yellow cake layer on top and spread its top with the green icing.

Top this with the blue cake layer and spread its top with the purple icing.IMG_2521

Refrigerate for 30 minutes or until icing is firm.

Cover the top (covering the purple icing) and sides of the cake with Fluffy Icing.IMG_2527


Let stand at room temperature before serving.

Fluffy Icing


1 c white corn syrup

2 egg whites

1/4 t cream of tartar

1 t vanilla


In saucepan, bring corn syrup to boil over high heat.

Meanwhile, in bowl set over just simmering water, beat the egg whites with cream of tartar until frothy.

Beat in corn syrup in a thin steady stream; beat for about 4 minutes or until stiff peaks form.IMG_2523

Remove from heat; beat in vanilla.

Butter Icing


1 c butter, softened

5 c icing sugar

⅓ c milk

2 t vanilla 


Beat butter until fluffy.

Gradually add in the sugar alternately with milk; 3 of sugar, 2 of milk.

Beat in vanilla.

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