Preheat the oven to 180ºC/Gas Mark 4.
In a bowl, beat the eggs with the sugar until a light and sparkling mixture is obtained.
Mix the flour with the baking powder and the lemon zest and add to the egg mixture. Add the ricotta cheese, continuing to mix. Add the berries and fold in gently.
Pour the mixture into a mould and cover with baking parchment, then bake in the oven for 45 minutes.