Preheat the oven to 400°F. Grease and flour a 9-inch round cake pan. I prefer to use a springform pan.

Cream the butter and sugar, add the egg yolks in one go, then add the lemon zest and lemon juice. In a separate bowl, whisk the egg whites until they form soft peaks and add to the mixture. Last, fold in the ground almonds and flour. Pour the mixture into the cake pan and bake in the oven for 10 minutes, then turn the oven down to 300°F and cook for another 40 minutes. Cool and invert the cake onto a serving plate. You can get creative with this: I was disgusting and iced it with a mixture of creme fraiche and lemon curd!