Taste the rainbow with a slice of this rainbow cake roll. Made with coconut flour, it’s a colourful, low-carb and gluten-free dessert that’s light, butter-free in the sponge and filled with a creamy sugar-free buttercream. It’s simple to make yet impressive on any celebration table.
This cake is fun to assemble and ideal for anyone wanting a vibrant, low-carb treat. The sponge is airy thanks to whipped egg whites, and the filling combines butter, cream cheese and a low-carb sweetener for a smooth, pipeable buttercream. With a little organisation during preparation you can pipe neat rainbow stripes and achieve a beautiful swirled roll.
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How to make a rainbow cake roll
To colour the sponge, divide the batter into portions and tint each with food colouring. You can use commercial gel or liquid food colouring, or natural alternatives if you prefer. I mixed orange from red and yellow to get the hue I wanted—those art class skills come in handy!
For piping I used disposable piping bags and sealed the open ends so the batter wouldn’t leak. This helps keep the lines tidy while you fill the pan.
The key is to be organised before you start piping: have bowls, colours and piping bags ready so you can move quickly and keep the batter aerated.
- Spoon the cake batter equally into six bowls.
- Add colouring to each bowl, working in rainbow order for the best effect.
- Transfer each coloured batter into piping bags.
- Pipe the colours into the lined baking tin. You can pipe each colour in a single block, repeat stripes, or pipe lengthways for different patterns.
- Bake until the sponge is set and firm to the touch.
- Cool briefly, fill with buttercream, and roll up the sponge to create the swirl.
More fun low carb cakes to make
Heart Cupcakes
Chocolate Covered Strawberries Cake
Battenberg Cake
Butterfly Cakes
Flourless Chocolate Cherry Roulade
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Rainbow Cake Roll
Angela Coleby
Pin Recipe
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Ingredients
- 5 medium eggs separated
- ⅓ cup coconut flour
- ½ cup monkfruit or other low-carb sweetener
- 1 teaspoon vanilla extract
- 1 teaspoon baking powder
- 6 food colourings rainbow colours
Filling
- 4 oz butter softened
- 4 oz cream cheese softened
- ¼ cup allulose or other low-carb sweetener
- 2 tablespoons cream heavy/whipping
- 1 teaspoon vanilla extract
Instructions
Make the Sponge
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Preheat the oven to 180°C / 350°F.
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Line up six small bowls and piping bags for colouring.
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Grease and line a 9 x 13 inch (22.9 x 33 cm) rectangular baking tin with parchment paper.
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Whisk the egg whites in a medium bowl until stiff peaks form.
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In another bowl, beat the egg yolks with vanilla and monkfruit until combined.
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Add the coconut flour, baking powder and a pinch of salt to the yolk mixture and whisk well.
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Gently fold the whipped egg whites into the batter until the colour is even and the mixture is light.
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Divide the batter evenly among the six bowls.
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Add a few drops of food colouring to each bowl until you reach the desired shades.
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Spoon each coloured batter into an icing bag and seal the open end to prevent leaking.
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Pipe the colours into the prepared pan in rainbow order, either lengthways or widthways.
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Bake for 15–20 minutes until the sponge is firm to the touch.
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Remove from the oven and cool in the tin for 5 minutes.
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Place a large sheet of parchment on the countertop, invert the tin so the sponge lands parchment-side up, and remove the tin.
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Using the top parchment layer, gently roll the sponge to shape it. This helps the cake hold its roll before filling.
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Set aside to cool completely while you make the filling.
Make the Filling
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Whisk the softened butter and cream cheese together until smooth.
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Add cream, allulose (or preferred sweetener) and vanilla, then beat until thick and silky.
To Assemble
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Carefully unroll the cooled sponge, peel away the top parchment and spread the buttercream evenly over the surface.
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Use the outer parchment to help roll the sponge back up tightly but gently.
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Trim the ends for a clean presentation.
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Slice and enjoy.
Notes
Net carbs are total carbs minus fiber; sugar alcohols are excluded. Nutritional values are estimates calculated from the ingredients and may vary depending on products and preparation.
Nutrition
The nutrition information is an estimate provided by an online nutrition calculator.
