First, preheat your oven to 160 deg C (320 F).
Line and grease a 25cm (10") cake pan with baking paper.
Wrap a coin in aluminium foil and set it aside.
Combine the all-purpose flour and baking powder in a bowl and set aside.
Mix the butter and sugar in a large bowl of your stand mixer until pale and creamy. (see note 4)
Turn the speed down to low and add the eggs one at a time, ensuring they are well incorporated.
Add the vanilla extract, orange juice, orange zest and brandy and mix well.
Add the flour mixture in two parts until you end up with a thick cake batter. (see note 5)
Add the coin and fold through the batter.
Pour the batter into the prepared cake pan and bake for one hour. Insert a toothpick into the centre to test if the vasilopita is ready. If it comes out clean, the cake is cooked.
Allow it to cool in the pan completely before inverting it onto a plate and dusting the top of the cake generously with powdered sugar.