Requires: 28cm round cake pan, electric mixer (or hand beater)
Preheat oven to 180°C conventional oven (400° Fahrenheit/Gas 6). Grease a 28cm round cake pan by lightly buttering the base and sides with margarine or butter. Line the base with baking paper, then lightly butter over the baking paper. Add a heaped tablespoon of flour, then turn and shake the tin to coat the butter in flour on the base and sides of the cake pan.
Place 200g pistachios into a food processor and process briefly. The mixture should have a combination of roughly chopped and finely chopped pistachios. Roughly chop extra pistachios for decoration and set aside.
Using an electric mixer or hand beater, beat the egg whites with a pinch of salt until stiff peaks form. With the mixer (or hand beater) running, add the egg yolks, one at a time. Add the sugar, one tablespoon at a time, beating well after each addition.
Use a wooden spoon to stir in the flour, one tablespoon at a time. You want to see air bubbles rise to the surface of the cake mixture before adding additional tablespoons of flour. Stir in the lemon juice. Then stir in the sesame oil and lemon zest until well combined. Stir the pistachios and sifted baking powder into the cake mixture.
Note: 00 is a powder-fine Italian type of flour. It is made from soft wheat varieties, and is frequently used in Italian desserts and pastas. 00 flour is available in most supermarkets, Italian food stores and gourmet delicatessens.
Pour the cake mixture into the prepared cake pan. Bake for 30 to 35 mins or until a skewer inserted in centre comes out clean. Allow the cake to cool in the cake pan for 10 minutes, then transfer to a wire rack to cool completely.
Meanwhile to make the Limoncello syrup, combine the water, Limoncello Liqueur and sugar in a small saucepan over low-medium heat. Bring to the boil, then remove from the heat. Set aside to cool slightly. Brush or spoon the syrup over the cake.
To make the Lemon icing, combine the icing sugar (confectioners’ sugar) and lemon juice in a small saucepan over low heat and continuously stir for a few minutes until well combined. Spread a thin layer of the icing over the pistachio and lemon cake. Decorate with chopped pistachios on top. Set aside for 20 minutes to set before serving – buon appetito.