Preheat oven to 180°C.
Beat the eggs and the cane sugar until pale and light. Stir in the olive oil and the lemon juice.
Sift together flour, baking powder and salt and fold into the cake batter.
Scrape a third of the batter into another bowl and fold in cocoa powder and cardamom powder.
Grease a 22 cm (9 inch) round cake pan and dust lightly with flour.
Add half of the plain batter into the pan, then add the cocoa batter in blobs on top. Add the rest of the plain batter and swirl with a skewer to create a marbled effect. Sprinkle the pine nuts on top.
Bake for about 30 minutes or until a toothpick inserted in the centre comes out clean.
Let it cool down completely before slicing it.