Upside Down Pistachio & Rhubarb Cake
This cake is one of those showstoppers that looks like you've been in the kitchen all day, but is totally worth every minute. We love the combo of tart pink rhubarb and rich, nutty pistachio sponge; it's zingy and indulgent all at once. When you flip it out of the tin and that rhubarb pattern is sitting there looking gorgeous on top, honestly, it never gets old. The lemon keeps everything feeling fresh and bright, and the pistachio gives the sponge this incredible dense, moist crumb that we are completely obsessed with. Make this for a dinner party, a birthday, or just because it's the weekend and you deserve something special.
Before You Start
- Preheat oven to 180°C
- 23cm round cake tin greased & lined with baking paper
- Food processor
- Stand mixer or electric whisk
- Warm oat milk & vinegar, set aside for 5 minutes
Ingredients
- 150ml - Oddlygood Vanilla Oat Drink
- 1 tbsp apple cider vinegar
- 125g pistachios
- 150g caster sugar
- 150g plant-based butter
- 300g plain flour
- 2 tsp baking powder
- ¼ tsp salt
- 1 lemon
- 300g stalks of rhubarb
- 1 tsp cornflour
- 1 tbsp sugar
Method
Prep the ingredients
- Gently warm the oat milk in the microwave or pan for 30 secs, add the vinegar and set aside for 5 minutes to curdle
- Place 100g of the pistachios in a food processor and blend to a fine powder
- Zest and juice lemon
- Slice the rhubarb into 4cm diagonal pieces
Prepare the rhubarb
- Put the rhubarb in a bowl and toss with the sugar and cornflour
- Arrange in the base of the lined cake tin
Bake the cake
- Beat the butter and caster sugar in the bowl of a freestanding electric mixer or with an electric whisk until pale and fluffy
- Whisk in the oat milk, then fold through the lemon zest, pistachios, flour, baking powder and salt
- Spoon into the cake tin over the rhubarb and level the top
- Bake for 35 minutes until a skewer comes out clean
- Remove from the oven and leave to cool for 5 mins in the tin before turning out onto a plate
- Roughly chop the remaining pistachios and scatter over the top to serve
Tips & Variations
- Get the rhubarb arrangement right: Take a bit of time laying the rhubarb in the tin before you pour the batter over. It's the top of the finished cake, so a nice diagonal pattern looks seriously impressive when you flip it out.
- Don't skip the resting time: When you add the vinegar to the oat milk, let it sit for the full 5 minutes. That curdling is doing important work and rushing it will affect the texture of your sponge.
- Save some whole pistachios for the top: We love scattering a handful of roughly chopped pistachios over the finished cake. Adds a bit of crunch and makes it look even more beautiful.
Why This Works
The trick here is blending the pistachios down to a fine powder so they become part of the sponge itself, giving it that incredible flavour and texture all the way through rather than just in pockets. The oat milk and vinegar combo is our go-to for creating a buttermilk effect in vegan baking. It makes the sponge light and tender and helps it rise beautifully. And tossing the rhubarb with sugar and cornflour before it goes in the tin means you get a gorgeous jammy layer on top when it flips, not a watery mess.