Pre-heat oven to 200C, turn down to 170C and place cake batter in for 10 minutes. Then turn down to 130C for 70 minutes.
Separate the eggs whites and yolks
Lightly grease the base and sides of the cake pan with butter ( tbsp from your 500g butter), and sprinkle lightly with flour. Turn the pan upside down at the sink and knock off any excess flour (old school method is still the best!)
Egg Mixture
Whip the egg whites on medium-high speed until foamy and sprinkle in the baking powder. Continue mixing to a stiff soft peak adding in the sugar slowly.
Add in the beaten egg yolks and gently whip for a minute to combine until thick and creamy looking.
Butter Batter
Place butter and condensed milk in the bowl. Beat on medium speed until light and fluffy. Add in the vanilla essence and or brandy.
Add half the Egg Mixture to the Butter Batter. Whipped till well mixed. Gently fold in the Flour Mixture and fold lightly together with the rest of the Egg Mixture.
Reduce the heat of your oven from 200C to 170C and bake for 10 minutes. Then reduce oven temperature to 130C for a further 70 minutes or until cake is cook. (My oven is fan assisted)
When cake is done, remove the pan from the oven and place on a cooling rack. Let the cake cool in the pan for about 20 or so minutes, then turn out onto a cooling rack to cool completely. This can take about an hour!
Notes
TIP - I am using cake flour in all my bakes as I buy them in 10 packs of 1kg each. I like using cake flours because it gives my bakes a finer texture. I sieved my cake flours twice in the winter months because of the damp wet weather.