This cake might be a stretch as a holiday cake, but, since I normally make Rainbow Cookies around the holidays I figured a Rainbow Cookie Cake would be a nice addition as a holiday cake. It definitely has a bit of a wow factor and it’s much easier & quicker to make than the cookie version.
One of the things that made this cake easy was using three boxes of white cake mix. I prepped each following the directions on the package and added in 1/2 teaspoon of almond extract to each. While the almond flavor was noticeable, I think it would have been better to add in 3/4 to 1 teaspoon of extract to each. Or, you could skip the extract altogether and grate in almond paste. I would suggest buying one package of almond paste and dividing it into three equal parts. Once the cake mix was prepped I then added in gel food coloring to achieve the pink, yellow & green colors. Here’s a tip, instead of adding a bunch of one color to achieve your desired shade, add in a little orange to the yellow, add a drop of red to the pink and a bit of blue for the green. This will also result in more vibrant shades of each color as well.
I baked each of the layers in a 9 inch square pan. While the directions said to bake the cakes in a 350 F oven for about 35 minutes, I found that after 30 minutes my cakes were still undercooked so I lowered the oven temperature to 325 F and baked the cakes for an additional 10-12 minutes. I let the layers cool in the pan for about 15 minutes and then inverted them on wire racks to cool completely.
Once the layers were cooled I leveled each of them with a serrated knife. I placed the pink layer on a cake board, trimmed side up, and spread about 1/2 cup of raspberry jam. I repeated this step with the yellow layer and then topped the cake the green layer, trimmed side down. While the directions called for the cake to be frozen for 1 hour, unfortunately I used a round cake board that wouldn’t fit in my freezer so I ended up refrigerating it for about 2-3 hours. Don’t worry if your layers are not flush, i.e. not the same width, you will be trimming the sides of the cake once you top it with chocolate. This ended up happening to me because while both of the pans I used were 9 inch squares the sides of one of the pans was straighter than the other.
Before removing the cake from the refrigerator I made the chocolate topping. I melted chocolate and butter together in the microwave in 30 second intervals. Well, to be truthful, I microwaved it once at 30 seconds and the second time at 45 seconds and then stirred it together until smooth. I set it aside for about 10-15 minutes so it could cool and thicken before pouring it on the cake. If you pour it right away the chocolate will be too thin and just run down the sides of cake when you try to spread it. Also, you won’t be able to create the usual wavy lines in the chocolate that rainbow cookies normally have.
Once the chocolate was ready I removed the cake from the refrigerator and poured the chocolate over the top and using an offset spatula I spread it into a thick even layer over the cake. And for the final touch, using the tines of a fork I created wavy lines in the chocolate. If you find that the chocolate isn’t holding the wavy pattern, wait a minute or two and then go over the patter again with the fork. It could just be that the chocolate needs to cool a bit more. I then returned the cake to the refrigerator so the chocolate could set, but, not harden.
And finally, I trimmed all for sides of the cake. I did find this part a bit tricky as my cake was crumbling while doing so. Partly because, as per the directions, I only used eggs whites in the batter which produces a much lighter cake. You could use whole eggs as opposed to the egg whites which would produce a denser and moister cake and one that is slightly yellower, which would be good when tinting the yellow layer of the cake.
So, everyone who tried this cake, including me, loved it. They all agreed that it was light and not crazy sweet. The perfect type of dessert.
Rainbow Cookie Cake
3 16 to 18–ounce boxed of white cake mix (plus the required ingredients)
1 1/2 teaspoons pure almond extract
Pink, yellow and green gel food coloring
1 cup seedless raspberry jam
2 4–ounce bars semisweet chocolate, chopped
6 tablespoons unsalted butter, cubed
Preheat the oven to 350 F. Spray a 9-inch square pan with baking spray and set aside.
Prepare 1 cake mix per box directions adding in 1/2 teaspoon of vanilla extract. Tint with the pink food coloring, stirring well making sure no white streaks remain. Transfer to the prepared pan and bake in the preheated oven for 35 minutes. Let cool in the pan for 15 minutes and then transfer to a wire rack to cool completely.
Repeat to make the yellow and green layers.
Trip the tops of each of the cakes to make level. Don’t worry if the widths of the cakes are different, you will even it out at the end.
Place the pink cake, trimmed side up, on a cake board and spread with 1/2 cup of jam. Top with the yellow cake, trimmed side up, and spread the remaining jam on top. Top with the green layer, trimmed side down. Freeze for 1 hour.
Microwave the chocolate and butter together in 30 second intervals, stirring after each, until melted and smooth. Let it cool slightly.
Pour the cooled chocolate over the top of the cake and using an offset spatula, spread the chocolate in a thick even layer over the cake.
Using the tines of a fork create a wavy lines pattern in the chocolate. Return the cake to the freezer so the chocolate can set, but not harden, about 15 minutes.
Using a long serrated knife trim all four sides of the cake.
You can use whole eggs as opposed to the recommended egg whites on the box directions
For a stronger almond taste try adding in more almond extract, or substituting it with almond paste.
To achieve brighter shades of pink, yellow and green, add a little red to the pink, orange to the yellow and blue to the green
You can place the cakes in the refrigerator as opposed to the freezer, but, will need to leave them in longer.
Recipe from Food Network