
Ruby-Red Grapefruit, Pistachio & Rosemary Cake
A delicious and moist flourless grapefruit cake made with the zest and juice of ruby-red grapefruit, ground pistachio and polenta. A simple gluten and dairy-free bake that everyone will enjoy.

Ruby-red Grapefruit & Pistachio Cake batter – ready to go in the oven. The cake batter is very liquid so I wouldn’t recommend using a loose-bottom cake tin. If this is all you have then fully line the tin as shown.
With grapefruit currently in season I simply couldn’t help myself but to use them in baking a cake. Ruby and pink grapefruit are in season from November through to May. Tart with a tinge of bitterness, grapefruit originated as a hybrid of pomelo and sweet orange.

Ruby-red Grapefruit, Pistachio and Rosemary Cake, gluten and dairy free.
I have had this recipe in my files for sometime and a cake I supplied to a local artisan coffee shop, it was one of their best sellers.
Consisting of just a few ingredients; eggs, ground unsalted pistachios, olive oil, fine polenta, sugar and of course grapefruit. The citrus syrup, steeped with rosemary, adds an extra flavour dimension, peppery with warm pine notes.
This tempting bake really couldn’t be more simple to make, all you’ll need in the way of equipment is a food processor to grind the nuts. I urge you to give it a try and please leave a comment or rate the recipe. Happy Baking!
Ruby-red Grapefruit Pistachio & Rosemary Cake
Equipment
- 20cm cake tin
Ingredients
- 110 g unsalted pistachios
- 1½ Ruby-red grapefruits
- 1 ½ tsp GF baking powder
- 90 g polenta
- 180 g golden caster sugar
- 4 large eggs 2 separated
- 190 g olive oil
Grapefruit & Rosemary Syrup
- 45 g golden caster sugar
- 90 ml grapefruit juice
- 1 spring rosemary
To decorate
- malden salt
- 20 g pistachios
- dried rose petals optional
- rosemary sprigs
Instructions
- Pre-heat the oven to 170°C fan. Line a 20cm cake tin with baking parchment.
- Begin with blitzing the pistachio to a fine meal and place in a bowl, add the polenta and baking powder, stir to combine. Zest the grapefruits and stir into the dry ingredients, set to one side.
- Next place the sugar and oil in a medium size bowl, with a balloon whisk combine. Add 2 eggs and 2 egg yolks, whisk again to a smooth batter. Fold the dry ingredients into the egg mixture. Whisk the egg whites with a pinch of salt until soft peaks form. Whisk a tablespoon into the cake batter, then fold the remainder in with a large metal spoon. The batter doesn't need to be completely smooth, if its marbled with egg white that's fine. Pour into the tin.
- Bake for 40-45 minutes or when a cocktail stick, inserted in the centre of the cake comes out clean.
- While the cake is baking, prepare the syrup. Pour the grapefruit juice into a small saucepan with the sugar and rosemary. Bring to a slow simmer. When the sugar has dissolved, remove from the heat. Set to one side to infuse.
- Fish out the rosemary from the syrup and spoon over the cake. Roughly chop the remaining nuts and sprinkle on the cake with a good pinch of Malden salt, rosemary sprigs and dried rose petals, if using.

Ruby-Red Grapefruit & Pistachio Cake – stays moist for several days.
Tips:
- If ruby grapefruit isn’t available, use pink as an alternative.
- Try using bay leaves instead of rosemary. Just one will do.
This is such a delicious cake. So moist and we like the fact that it’s made with polenta and olive oil and so flavoursome with the grapefruit. I will definitely make this again.
So glad you like it, it keeps fir several days too, if it lasts that long!