Mix butter and sugar together until the mixture is creamy.
Add the eggs one at a time, mixing well after each addition.
Add the heavy cream and mix evenly.
Sift in cake flour and baking powder, and gently fold them in.
Pour the batter into the mold and smooth the surface.
Bake in a 170°C oven for 40-45 minutes.
Let it cool completely on a wire rack.