Passionfruit & coconut cake

Name: Passionfruit & coconut cake
Prep time: 15 min
Cook time: 50 min
Total time: 1 h 5 min
Cuisine: American
Ingredients: Vegetable oil, to grease; 175g unsalted butter, at room temperature; 215g (1 cup) caster sugar; 3 eggs, lightly whisked; 200g (1 1/3 cups) self-raising flour, sifted; 50g (2/3 cup) shredded coconut; 1/2 tsp baking powder; 125g (1/2 cup) sour cream; Shredded coconut, extra, to decorate; 3 large passionfruit, halved; 150g (1 cup) icing sugar mixture, sifted; 125g unsalted butter, at room temperature