A fluffy and zingy grapefruit loaf cake recipe with rhubarb buttercream
The grapefruit juice and almonds in the sponge make this cake irresistibly moreish, and the buttercream technique will change the way you think about icing forever.
If you’re after the perfect cake for hosting—whether it’s afternoon tea, lunch, a birthday, or simply the weekend—this grapefruit loaf has you covered. The combo of the zesty grapefruit and zingy rhubarb is perfect for spring, and the beauty of this cake is that the rhubarb can easily be swapped for any fruity compote you have to hand, or just leave the icing plain. It's as easy as that, and can be made all year round!
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Yields:
10 serving(s)
Prep Time:
30 mins
Cook Time:
40 mins
Total Time:
1 hr 10 mins
Cal/Serv:
564
Ingredients
For the cake:
200 g unsalted butter, softened
200 g golden caster sugar
2 pink or red grapefruits (zest and juice)
3 eggs
200 g plain flour
100 g ground almonds
1/2 tsp. baking powder
1/2 tsp. bicarbonate of soda
1/4 tsp. salt
For the rhubarb buttercream:
200 g unsalted butter, softened
120 g icing sugar
25 ml hot water
1 1/2 Tbsp. cream, room temperature
1/2 tsp. vanilla extract
1/4 tsp. salt (if using unsalted butter)
80 g rhubarb compote
For the rhubarb compote:
150 g rhubarb, cut into 2–3 cm pieces
30 g caster sugar
1 Tbsp. grapefruit juice
Directions
Step 1Preheat the oven to 180°C (160°C fan), gas mark 4. Grease and line a loaf tin.
Step 2Beat the butter and sugar together for about 3 minutes, until light and fluffy.
Step 3Add the eggs one at a time, alternating with the ground almonds, mixing well after each addition.
Step 4Whisk in the grapefruit zest and juice (reserving a little zest for topping).
Step 5On a low speed, mix in the flour, baking powder, bicarbonate of soda and salt until just combined.
Step 6Pour the mixture into the prepared tin and level the surface. Bake for 40–45 minutes, or until a skewer inserted into the centre comes out clean.
Step 7Leave to cool completely before removing from the tin.
Step 8Put the rhubarb, sugar and grapefruit juice into a pan. Cook over a medium heat until the rhubarb breaks down and the mixture becomes thick and jammy. Leave to cool.
Step 9Whip the softened butter using a paddle attachment (or electric whisk) for about 3 minutes, until very light and fluffy.
Step 10Mix the icing sugar with the hot water to form a smooth paste. On a low speed, gradually add the sugar mixture to the butter.
Step 11Mix in the cream, vanilla and salt. Add the rhubarb compote and a squeeze of grapefruit juice, then whip until smooth. If the mixture looks split, continue mixing on low and it will come back together.
Step 12Spread the buttercream over the cooled cake and sprinkle with the reserved grapefruit zest.
GH tips:
Mix the batter as little as possible once the flour is added to keep the sponge soft and tender.
Use the extra compote on yoghurt for a breakfast treat.
If you can’t find rhubarb, use fresh or frozen mixed berries instead.
Shop-bought compote or jam works well as a shortcut.
The GH Kitchen Team are Good Housekeeping’s resident recipe developers and all-round food obsessives. GH Kitchen Director Sarah Akhurst is our resident hosting pro and loves nothing more than putting on a foodie feast for friends. Our GH Kitchen Manager Linzi Pucino is our very own Italian food expert (originally hailing from the North East of Scotland!) and can be found working her way through midweek recipes that cover all bases, from haggis to ragu! Our Kitchen Editor Nadine Brown loves digging into the stories behind her favourite foods and enjoys applying her eclectic tastes to more modern, flavour-forward recipes - just don't give her too much chilli! Our Junior Food Content Produce Frankie Prichard combines a love of beautiful presentation and flavour-led, seasonal cooking in her recipe development, along with a passion for bringing people together through food. With a wealth of professional kitchen experience between them, they’re dedicated to ensuring every Good Housekeeping recipe is the best it can be, so you can trust they’ll work every single time
Frankie is the Junior Food Content Producer, developing, testing and refining recipes, as well as creating fun, educational content across the GH Kitchen’s print and digital platforms. While studying Communications and Media, her passion for bringing people together through food quickly found its place in the kitchen, leading to a career shaped by hands-on experience in the hospitality industry. Now, she brings that same energy and creativity into the world of food publishing. Previously, Frankie trained as both a baker and chef at Landrace Bakery and Upstairs restaurant in Bath, Somerset. She has also worked as a freelance assistant food stylist and private chef in London, combining a love of beautiful presentation with flavour-led, seasonal cooking.
