Stephen Mercer has been cooking commercially for more than 20 years, yet still retains a love for it that he believes would be rare in most other industries. "While we serve this with elaborate accompaniments including rhubarb sorbet and roasted strawberries at Mercer's, the cake is easy to make and can be served on its own or simply with whipped cream."
200g shelled pistachio nuts
50g plain flour
1 tsp baking powder
100ml olive oil
200g castor sugar
Juice and zest of 1 lemon
Juice of 1 orange
Preheat oven to 160C
Process the pistachios in a food processor until finely ground, add the polenta, flour and baking powder.
Melt the butter and add it to the olive oil
Whisk the eggs with the sugar until light
Add the oil and butter mixture
Whisk in the pistachio mixture
Whisk in the juices and zest
Bake in a greased and floured tin at 160C for 45 minutes
Rest in the tin for 10 minutes, then turn out and cool on a cake rack.