Pre-heat oven to 160 degrees Celsius, and line two 20cm round springform cake tins.
In the bowl of an electric mixer, beat the butter, sugar and vanilla for about 2 minutes or until light and fluffy.
Beat in the eggs one at a time, mixing well after each.
Add half the flour and gently mix to combine. Then add the milk and slowly mix until combined. Add the remaining flour and mix gently until just combined.
Divide the batter evenly between the two tins, and smooth the top of each. Bake for 45 minutes or until a skewer comes out clean.
Leave the cakes to cool in their tins for a few minutes, before turning out onto a wire rack to cool completely.
To make the icing, beat the butter with the vanilla using a stand mixer and the paddle attachment for 1-2 minutes, or until it is pale and creamy. Add in the icing sugar and beat for another 1-2 minutes or until the icing is fluffy - covering your mixer with a tea towel at this point could be helpful!
Add in a small amount of pink food colouring and mix until combined. Continue to add in pink food colouring a little at a time until you reach your desired colour.
Cut each cake in half so you have four cake layers. Place one cake on a serving plate or cake stand. Using a piping bag or a zip lock bag, pipe an icing border around the edge of the cake, then go over this border again with another layer of icing. This border will keep the filling from spilling out into the icing on the finished cake.
Fill the centre of the cake with a third of the passionfruit curd and smooth it out until it reaches your buttercream border, then place on cake on top and gently push it down so it sits evenly on the layer beneath. Repeat with the other two layers, placing the next cake half top side down, then finishing with the last cake half bottom side up so you have the most even layer on top.
Using a spatula, smooth the buttercream over the top of the cake, and down the sides so the whole cake is covered in buttercream. If your buttercream becomes too soft, place it in the fridge for a while to firm up a little before continuing.
Just before serving, place small amounts of the edible gold leaf randomly all over the cake. It is easiest to apply the gold leaf to the icing gently with a small soft paint brush.
Then decorate the entire cake with the edible flowers, gently pressing them into the cake so the petals stick to the icing. The flowers will stick to the cake easiest if the cake is at room temperature.
Decoration best enjoyed same day as application.