Slice the tops and bottoms off the cakes to smooth the surface and remove any excess browning.
Place the first cake on your work surface and brush generously with the syrup. Spread some buttercream onto the surface, then repeat with another layer of cake, syrup, buttercream and then the final layer of cake. Do not brush this layer of cake with the syrup.
Coat the cake in a thin layer of buttercream, called a crumb coat. This will catch any excess cake crumbs. Chill the cake in the fridge for 20 minutes.
Coat the cake in a thick, generous layer of buttercream. Use a palette knife to smooth the sides of the cake. Top with fresh flowers and enjoy!