Spray a 23cm round cake pan with Moro Pure Spray Primero Extra Virgin Olive Oil and line with baking paper. Sift together flour, sugar, baking powder and salt. Beat eggs with an electric mixer for 5 minutes until thick and fluffy. Gradually beat in Moro Primero Extra Virgin Olive Oil and juice of 1 orange in a steady stream. Reserve 2 tablespoons pistachios for garnish and fold the rest into the mixture with the flour. Pour into cake pan. Bake at 180°C for 40-45 minutes or until golden and cooked when tested (a skewer inserted in the centre will come out clean). Meanwhile, remove the skin of the remaining oranges with a sharp knife and cut the flesh into slices. Heat caster sugar and orange liqueur until dissolved. Add orange slices and allow to cool.

Turn cake out onto a wire rack to cool and garnish with liqueur oranges and reserved pistachios.