Rainbow Roll Cake
Rainbow roll cake is a whimsical, bright cake that is moist and sweet with a creamy buttercream filling inside.
Ingredients
Rainbow Cake
- ¾ cup all-purpose flour
- 1 teaspoon baking powder
- ½ teaspoon salt
- 4 large eggs room temperature
- ½ cup granulated sugar
- 3 tablespoons vegetable oil
- 1½ teaspoons pure vanilla extract
- ½ teaspoon pure almond extract
- gel food coloring red, orange, yellow, green, blue, and purple
- Powdered sugar for dusting
Buttercream Filling
- ¾ cup salted sweet cream butter softened
- 1 teaspoon clear vanilla flavoring
- ½ teaspoon almond extract
- 2 cups powdered sugar
- 2 tablespoons heavy cream
Instructions
Rainbow Cake
- Preheat the oven to 350°F. Line a 10x15x1-inch baking sheet (jelly roll pan) with parchment paper. Set it aside.
- Add the flour, baking powder, and salt to a small mixing bowl. Whisk to combine.
- Using either a stand mixer or a medium-sized mixing bowl and a handheld mixer on high speed, beat together the eggs, sugar, vegetable oil, vanilla, and almond extract for 5 to 6 minutes, until thickened and light yellow.
- Gently fold in the flour mixture until combined.
- Quickly and gently divide the batter between 6 bowls (about ⅔ cup each).
- Add 1 color of the gel food color per bowl. Depending on how dark you want to tint the batter, we recommend 3 to 5 drops. Gently fold the gel into the cake batter.
- Spoon the individual colors into 6 disposable piping bags or quart-size ziplock bags. Secure the tops of the bags.
- Lightly spray the prepared baking sheet with nonstick spray, paying close attention to the edges.
- Snip off a small corner of the bag. Starting at 1 corner of the prepared baking sheet, gently squeeze a small amount of the red batter. Be sure to keep the line as straight as possible. Next, gently squeeze a line of orange batter ¾ inch-1 inch wide. Next, the yellow, green, blue, and purple. Continue until the pan has been covered. Lightly tap the pan on the counter to remove any air bubbles in the cake batter. Bake for 8 minutes.
- Remove the pan from the oven. Measure out a piece of parchment paper to roll the cake in. You will need to leave about a 2-inch overhang to begin the cake roll. Lightly dust the baked cake.
- Have a large cutting board or cooling rack ready to aid in the cake transfer.
- While the cake is warm, lay the piece of parchment paper over the powdered sugar-dusted cake. Place the cutting board (or cooling rack) on top of the parchment. Carefully flip the cake over so that the cake is resting on the dusted piece of parchment and cutting board/cooling rack.
- Remove the upside-down cake pan, and carefully peel off the parchment paper that the cake was baked on.
- Fold the overhanging end of the parchment paper up onto the cake and then gently and patiently start rolling the shorter side of the cake towards the other short side. The parchment paper will be rolled up inside the cake. Once rolled, transfer to a cooling rack to finish cooling completely.
Buttercream Filling
- Using either a stand mixer or a medium-sized mixing bowl and a handheld mixer on medium-high speed, beat the softened butter for 1 to 1½ minutes until smooth.
- Add the clear vanilla and the almond extract and continue mixing for another 30 seconds.
- Lower the mixer speed to low, and beat in the powdered sugar 1 cup at a time. Alternate with the heavy cream. Increase the speed back up to medium-high and continue mixing for 1 more minute until smooth.
- Once the cake has completely cooled, gently unroll the cake. Using either a silicone spatula or an offset spatula, spread the filling over the surface of the cake roll, avoiding the outer edges.
- Tear off 2 sheets of plastic wrap to overlap the long edges and lightly spray with nonstick spray. This is for tightly wrapping the filled cake roll.
- Slowly roll the cake back up as before. Transfer the cake roll to the prepared plastic wrap. Roll the finished cake roll up in the plastic wrap. Once finished wrapping, twist the ends tightly to seal the cake roll securely. Chill in the refrigerator for 6 hours. Remove just before serving to slice the cake into ten ½-inch slices.
Notes
Make sure you are using an actual jelly roll pan. You cannot substitute a cookie sheet for a jelly roll pan as it will not produce the cake you are hoping for.
It is very important to be gentle when folding in the flour and the color. It’s important to keep as much of the air bubbles in the batter as possible to keep the cake fluffy.
Place each bag in a bowl or cup with the cut end up so the batter doesn’t spill out while piping the layers in the cake pan.
Oven temperatures vary and may need to be recalibrated periodically to ensure they are accurate. Make sure to keep a close eye on your cake as the suggested baking time approaches.
You can use a tea towel to wrap the warm cake roll in, but the rainbow colors will stain the tea towel. The parchment paper is disposable and will not stain.
Be patient when rolling and unrolling the cake roll. Unrolling too quickly can cause cracks in the cake.