Blog with Friends - Rainbow Sheet Cake

Welcome back to Blog with Friends. Not surprisingly this month's theme is right up my alley - it's "Rainbow", and you know how much I love St. Patrick's Day! I blog every year about projects like the wooden rainbow we painted or the shamrock cookies we baked, but I realized I never went into the rainbow sheet cake that turned out so pretty.

I'll make good for it now.


Google or draw a rainbow template. Depending on the size, duplicate so you have 6-8 rainbows per cookie sheet.

Make your batter using the following 


2 eggs
1 cup granulated sugar (225g)
1 lemon, zest and juice
0.5 cup butter, room temperature (120g)
1 cup all purpose flour (125g)
1 tsp of baking powder
1 pinch of salt


Divide into six small bowls, eyeball the portions, you will need the largest amount of batter for the red and only 3-4 tablespoons for the purple one.

Dye them with red, orange, yellow, green, blue and purple food coloring gel. I didn't think of taking a picture of the pretty rainbow colored bowls until after I was done...

Fill them into individual plastic or piping bags.

Put your templates underneath your parchment paper and fix them with some tape (make sure to remove tape before baking):

"Paint" on the parchment paper, using a pastry bag filled with your batter. 

I have used this technique before to make ABC block squares, the IKEA cake and the playoff hockey puck brownies. Just keep in mind that if you use it for a different project that involves writing, you need to "mirror" the message for it to come out correctly in the end, because the bottom side will be visible after baking.

Start with red because in my opinion it's easier to continue underneath the bow.

Continue with the other colors.

Very important: put your tray in the freezer for at least an hour or more. You want your painting to become firm, so when you pour the "cover batter" over it, your piece of art won't get destroyed.

Depending on your preference our second batter may be a brownie batter or a lemon sheet cake recipe, I went for lemon:


4 eggs, separated
1.5 cups (300g) granulated white sugar
1 lemon, zest and juice
0.5 cups (120ml) sparkling water
0.66 cups (150ml) sunflower oil
2.5 cups (300g) all purpose flour
1 pack (3.75 teaspoons or 15g) baking powder
1 pinch salt


Preheat your oven: 180°C / 350°F

Beat the egg whites until they form firm peaks, set aside.
In a separate bowl mix together egg yolks, sugar and lemon zest until light and fluffy.
Pour in water, oil and lemon juice, mix carefully.
Add flour mixture.
Fold in egg whites

Pour on your special baking sheet, making sure all the rainbows are covered,

bake for about 20 minutes, test with a toothpick.

Let it cool, turn, and carefully remove the parchment paper. Tadaaaa!

Are you smiling? I was!

Cut into individual pieces, serve and enjoy!

Now please check out my fellow bloggers' creative contributions:

Karen of Baking In A Tornado made yummy cinnamon rolls shaped like shamrocks. 

Jules of The Bergham Chronicles put together a list of affordable rainbow items that can be bought to add color to your life.

Dawn of Spatulas On Parade came up with muffins and candy treats filled with sprinkles and fruit.

Melissa of My Heartfelt Sentiments brings color to your world with handmade cards.

Lydia of Cluttered Genius knows a way to find the gold.

With those colorful ideas I'm pretty sure we are super close to finding the pot of gold. 
Happy St. Patrick's week! Have fun out there!

PS: This just happened earlier today, thought I'd share it with you: