Member's Recipe: Courgette Cake
75g unsalted butter
75g caster sugar
Juice of approx 4 limes
Melt the butter in a heavy based saucepan, add all the other ingredients and whisk to a custard over a gentle heat. Let cool before filling the cake. The recipe suggests that if the lime curd needs firming up, just place the cake in the fridge for a while.