Double (Rainbow) Guest Attempt: Rainbow Cake

Is there anything (at least momentarily) more hopeful than a rainbow? Yes, you guessed it: Double rainbow!

(via Martha Stewart) Whisk Kid's version:

photo by Kaitlin Flannery of Whisk Kid

Sara's version:

photo by Sara Moe

Evin's version:

photo by Evin Watson

Sara's photographic recap:

Evin's recap:
My two year old daughter insisted on a rainbows-and-polka-dots themed birthday. Our friend, Jodi found that Martha Stewart had the perfect solution, a six-layer rainbow cake. I laughed when I saw the photo.

I have no real cake-making skills. The ridiculous height didn't concern me, however the color; the essence of the rainbow; how do you get those colors with that crappy, gnome shaped grocery store food coloring? The answer: gel food coloring. That is lesson number one and maybe the only one learned from this recipe, but its effect on me is immeasurable. There is no mixing liquids and ending up with dull colors and stained fingers. You just buy the gel food coloring that matches the color you are going for. Simple. And there are millions of colors to choose from. It can't be found at the grocery store, but William Sonoma seems to have it on their website, and I'm sure it is common in any baking specialty store. I got ours at this amazing baking store called NY Cake. (There is also a location in LA.)

The recipe instructs you to make the batter for all six layers at once, divide it evenly, and then add the colors. After adding the coloring, the vibrant batter immediately reminded me of that multi-colored custard they had the food fight with in Hook. Remember? They don't have food or parents, but the lost boys use their imagination to fill their bowls with roasted meat and colorful custard.

Once you've added the color to the batter everything else is straightforward. I have to say we were really impressed with the result. We didn't manage to get the icing between the layers to go on as thick as we wanted. The bands of white in Martha's cake look so good. I don't think it worked because the layers didn't cool all the way before we iced. (We don't have wire cooling racks. Those might have come in handy.)

In the end the end, we stuck to the recipe as best we could. The only thing different is the lack of sprinkles on the outside, which would have made a lot of sense. Because what is better than one rainbow? DOUBLE RAINBOW!!

OK, so I stole Evin's double rainbow joke for the first line of this post, but stand by the theft as I feel that the double rainbow joke needed to be doubly mentioned. Also: a big thank you to Evin, Keeley, Sara, and Sean for sharing! You guys are amazing. 

And lastly: this post feels a little awkward coming after what has happened and is still happening in Japan. I think Tim from Lottie + Doof summed up this confusion and awkwardness quite nicely here. And while making rainbow cakes and milk punch certainly can't hurt, I hope we can all finds ways to help. 
UPDATE! Another way to help: Heath Ceramics is donating 25% of online sales now through March 24th to Architecture for Humanity's rebuilding efforts in Japan. Check it out here.

Recipe via Martha Stewart via Whisk Kid!
Makes one 9-inch-round six-layer cake.

Ingredients
vegetable shortening
3 cups all-purpose flour
4 teaspoons baking powder
1/2 teaspoon salt
2 sticks (1 cup) unsalted butter, room temperature
2 1/3 cups sugar
5 large egg whites, room temperature
2 teaspoons pure vanilla extract
1 1/2 cups milk, room temperature
Red, orange, yellow, green, blue, and purple gel food coloring
Lemony Swiss Meringue Buttercream

Directions
Preheat oven to 350 degrees. Brush six 9-inch-round cake pans (or as many 9-inch cake pans as you have, reusing them as necessary) with shortening. Line bottom of each cake pan with parchment paper; brush again and set aside.

In a large bowl, whisk together flour, baking powder and salt; set aside. In the bowl of an electric mixer fitted with the paddle attachment, cream together butter and sugar. Slowly add egg whites and mix until well combined. Add vanilla and mix until fully incorporated. Add flour mixture and milk in two alternating additions, beginning with the flour and ending with the milk. Mix until well combined.

Divide batter evenly between six medium bowls. Add enough of each color of food coloring to each bowl, whisking, until desired shade is reached. Transfer each color to an individual cake pan. Transfer to oven and bake until a cake tester inserted into the center of each cake comes out clean, about 15 minutes (working in batches if necessary).

Remove cakes from oven and transfer to a wire rack; let cool for 10 minutes. Invert cakes onto a wire rack; re-invert and let cool completely.

Using a serrated knife, trim tops of cakes to make level. Place four strips of parchment paper around perimeter of a serving plate or lazy Susan. Place the purple layer on the cake plate. Spread a scant 1 cup buttercream filling over the first layer with a small offset spatula so it extends just beyond edges. Repeat process with blue, green, yellow, and orange layers.

Place the remaining red layer on top, bottom-side up. Gently sweep away any loose crumbs with a pastry brush. Using an offset spatula, cover the top and sides with a thin layer of frosting (also use any of the excess frosting visible between the layers). Refrigerate until set, about 30 minutes.
Using an offset spatula, cover cake again with remaining frosting.