You may have seen the DIY Rainbow Sprinkle Cake that we featured last fall. It traveled around Pinterest and became one of our top posts of 2012. If you missed it, it was delightful — and now the talented baker behind that tutorial is back with another easy, achievable DIY. Kate Wagner of The Greedy Baker uses everyday items to decorate a spectacular rainbow cake suitable for any celebration. Bright, vivid and simple, this technique uses common kitchen tools like zip-top bags and spoons. Introducing a DIY Rainbow Petal Cake!
This petal-style buttercream decoration is straightforward yet striking. It requires no special tools—just a few everyday items and basic buttercream skills. Gather your materials and let’s get started.
RAINBOW BUTTERCREAM PETAL CAKE
a DIY by Kate Wagner
Materials:
- 6″ crumb-coated cake, chilled
- Cake board or plate
- Skewer or toothpick
- Ruler
- 3 cups buttercream
- Food coloring for icing/frosting
- 6 zip-top bags
- Teaspoon
- Paper towel
- Scissors
- Turntable (optional)
- 6 glasses or cups
STEP ONE: Place your chilled, crumb-coated cake on a turntable if you have one. Measure the cake’s height and mark the midpoint all the way around with a skewer or toothpick, using the ruler as a guide. For example, a 4″ cake is marked at 2″. This line helps keep your piped dots consistent and even.
STEP TWO: Divide the buttercream into six portions of roughly 1/2 cup each and tint each portion the colors you want. In this tutorial, an electric gel range was used. Fill each zip-top bag with one color and snip about 1/4″ off the tip of each bag.
STEP THREE: Stand each filled bag in a glass and arrange the glasses in the order you wish to pipe. This keeps your workspace tidy and helps maintain your color sequence.
STEP FOUR: Pipe your first row of dots around the cake using the midpoint guideline. Pipe three dots above the line and three below to form a balanced first row.
STEP FIVE: Hold a teaspoon behind each dot and gently swipe it to one side to create the petal shape. Wipe the spoon with a paper towel between swipes so colors remain clean and separate.
STEP SIX: Continue piping rows of dots and swiping to form petals. Pause occasionally to check that your rows remain vertically aligned.
STEP SEVEN: When you return to your starting point, finish with a row of unswiped dots at the back of the cake.
STEP EIGHT: Chill the cake for about 10 minutes before decorating the top. Once chilled, pipe a ring of dots around the outer edge of the top and swipe each dot toward the center.
STEP NINE: Repeat piping and swiping toward the center until you end with a single dot in the center. Alternatively, you can finish the top in a spiral: start at the outer edge, pipe a dot, swipe, and continue inward until reaching the center, finishing with one dot.
STEP TEN: Step back and admire your rainbow petal cake. Slice, serve and enjoy!
Experiment with different color combinations and patterns—this buttercream petal technique offers lots of creative possibilities.
VENDORS & CREDITS:
Cake & Tutorial: Kate Wagner of The Greedy Baker
Find more cake projects and tutorials in our DIY Section!
