When my friend asked if I would bake something for her son’s 3rd birthday, I was thrilled. Not only did it give me an excuse to make a layer cake (yay!), but it also meant that she thought my cakes were good enough to serve at her party (which meant a lot to me). She also pretty much gave me free reign to do what I want. Her only instructions were, “think boy & color”.
After doing some thinking, I decided I would do a rainbow cake, but this time in a blue and green theme. I used the same recipe for the cake as last time, but used different shades of blue and green instead of the rainbow colors. For the frosting, I used the lemon Swiss meringue buttercream that goes with the original rainbow cake from Whisk Kid. I’m so happy I made that frosting, because it is seriously good! I also made some homemade lemon-flavored sprinkles to decorate the cake with (I made dyed them some of the same colors that I used in the cake), and added some store-bought gold star sprinkles for some sparkly fun.
Happily, my friend loved it 🙂
2 sticks (226 g) butter, room temp
2 1/3 c (466 g) sugar
5 egg whites, room temp
2 teaspoons vanilla
3 c (375 g) flour
4 tsp baking powder
½ tsp salt
1 1/2 c (355 g) milk, warmed for 30 sec in microwave to bring to room temp
Royal blue, Turquoise, Teal, Sky Blue, and Leaf Green (I used leaf green for both the dark & light green layers) gel food coloring.
1. Preheat the oven to 350°F degrees. Oil and line how ever many 9” cake pans you have (I have three and I just reused them).2. Sift together the flour, baking powder and salt. Set aside.3. Cream the sugar and butter, then add the egg whites (I cracked them all into one bowl) and add them a little at a time. Add the vanilla and mix until fully incorporated. Then, alternating between wet and dry, add the milk and flour mixture in two parts.
4. Divide the batter amongst 6 bowls (I did it by weight). Weigh your mixing bowl before you begin adding ingredients and then subtract the weight of the bowl from the final measurement after the batter is completed. Divide that number by six and add that weight of batter to each bowl), and then whisk a fair amount of the appropriate food color into each bowl. Keep in mind that the color of the unbaked batter will be the color of the baked batter. Pour into the pans and bake for 15 minutes each.
5. When you remove them from the oven, let them rest on the cooling rack, in the pan, for ten minutes. Then flip, cover, and stash them in the fridge to cool quickly.
Lemony Swiss Meringue Buttercream
To fill and crumb coat:
5 egg whites
1. Cook the egg whites and sugar in a small saucepan over medium heat, whisking constantly, until the sugar is completely dissolved (test by rubbing some between your fingers. If it’s completely smooth, it’s done). Pour into another bowl (a stand mixer is preferable) and whip on high speed until room temp. Then, on a medium-slow speed, add the butter, waiting until each piece is completely incorporated before adding the next. After all the butter has been added, turn the mixer back to high speed and whip until it has come together, about five minutes. Add the extract, beat briefly and then use.
2. If the buttercream seems soupy after all of the butter is added and does not come together after whipping, refrigerate for 5 to 7 minutes and continue whipping until it becomes fluffy and workable.
*Adapted from Whisk Kid
Lemon Flavored Sprinkles
8 ounces powdered sugar
3 3/4 ounces corn syrup
1/2 teaspoon salt
1 Tablespoon lemon extract (I used Lemon Bakery Emulsion)
1 Tablespoon Limoncello
Assorted food colorings
1. Combine all of the ingredients, except for the food coloring, in the bowl of a stand mixer fitted with a paddle attachment. Mix on the lowest setting until it forms a stiff paste. Add extra liquid only if absolutely necessary to achieve a pipe-able consistency.
2. Divide the paste into as many portions as you have color and tint each however you like.
3. Put one of the colored pastes into a piping bag fitted with a small round tip, and pipe the mixture into long, skinny lines onto parchment paper.
4. Repeat the process with the remaining colors and allow to dry, uncovered, for 48 hours. Depending on the weather conditions where you live, this could take more or less time. A humid climate may prolong the process and those living in an arid place may find they dry quite speedily. regardless of how long it may take to dry in your locale, the important thing is to dry them out to the core. Check by cutting into one of the piped sprinkle lines. If the cut piece lifts easily from the parchment and does not feel squishy to the touch, it’s ready.
5. Use a bench scraper or knife to scrape the dried sprinkle lines off the parchment. Break/chop the lines into fairly long pieces for “jimmies” or mince for “hundreds and thousands”.
6. Store in an airtight container indefinitely.
*Adapted from Brave Tart