Looking for a rainy-day baking project, I had a lightbulb recipe moment: We could make a rainbow cake without turning on the oven and using just four ingredients with a classic back-of-the box recipe. And so on this rainy day, a rainbow icebox cake was born.
All the flavors you know and love from icebox cake — soft, chocolatey wafers and cool, lightly sweetened whipped cream — are made more magical with a little food coloring and sprinkles. Here’s how to be a rainbow cake hero using just four ingredients.
Easy Rainbow Icebox Cake
Serves 8 to 10
3 cups cold heavy cream
1/4 cup powdered sugar
Liquid food coloring
1 (9-ounce) package thin chocolate wafer cookies, such as Nabisco Famous
Place the cream in the bowl of a stand mixer with a whisk attachment. (Alternatively, use an electric hand mixer and a large bowl.) Beat on medium speed until barely thickened, then add the powdered sugar and continue whipping to soft peaks. The cream will be further whipped with the food coloring, so do not whip the cream to medium peaks.
Place 5 small bowls on a work surface, then transfer 3/4 cup of the whipped cream into each one; set the remaining whipped cream aside. Color each small bowl with a drop of liquid food coloring and whip with a whisk to medium peaks. Whisk the uncolored whipped cream until thickened to medium peaks.
Spoon about 1 tablespoon of a colored whipped cream onto a cookie. Top with another cookie and another 1 tablespoon of a different-colored whipped cream. Continue layering cookies and colored whipped cream, alternating colors. Once you have a stack of 5 to 6 filled cookies, lay the stack on its side on a serving platter. Continue alternating the colored whipped cream with the cookies until all of the cookies are used, placing the stacks in one long row.
Cover the cookie log with the reserved uncolored whipped cream. If you’ve got any rainbow whipped cream leftover, feel free to swirl it into the top layer of whipped cream. Refrigerate the cake for at least 4 hours before slicing. Decorate the cake with sprinkles just before serving. Slice on the diagonal to reveal all of the colored layers inside.