Make a cream of butter, oil, sugar, invert sugar, salt, lime zest and juice and pistachio paste. Add the eggs one by one and mix until smooth. Add the flour and potato starch in batches and mix well until a smooth mass forms. Fill three quarters of a round wooden baking mould with the mixture. Halve and pit the plums and place them on top of the moelleux. Bake the moelleux for 25 minutes at 170°C.

Whip the whipping cream, Zusto and cadamom until soft. Add the pistachio paste and mix carefully. Transfer the cream to a piping bag with a French star nozzle.