Preheat the oven to 180 degrees
Butter the sides of the cake pan, line the bottom with parchment paper
Tip all the cake ingredients into the bowl of a stand mixer and beat for 2-3 minutes, until homogenous.
Dump the mixture into the pan, even out the surface with a spatula. Bake for 30-40 minutes
While the cake is baking, prepare the icing: mix the lemon juice with sugar, pour the mixture onto the cake while it is still hot, leave to cool.
Cut the cake into 15 squares.