Preheat the oven at 170°C.
In a small bowl, break an egg and briefly mix it.
Add the sugar, and use a hand mixer to beat the egg until it turns white.
Sieve the flour in 2 batches, fold briefly to combine.
Add the melted butter in a few batches, fold to mix until it just combines.
In the 2 cake forms, line with baking paper. Divide the cake batter equally into the two forms by dropping the batter from the center, around 15 cm above.
Bake for 12-15mins, or until the top turns golden brown.
Cool it down in the form for 5 mins. Then carefully tear the baking paper around the cake. Put the cake and cake form upside down, on top of a kitchen paper to cool down completely. (Tip: You can make the cake the day before, and wrap it with cling film, and put it in the fridge.)