Preheat the oven to 180 degrees celsius. Grease and line the cake tins with parchment paper.
In a big bowl of the stand mixer, add the egg whites and using a whisk attachment of a stand mixer. Whisk until stiff peaks are formed.
Keep the stiff egg whites separate until its needed.
In an another bowl, add the butter and sugar and cream until light and fluffy.
Add and whisk the egg yolks, half of the milk and lemon zest.
Sift the flour and baking powder into the wet mixture.
Add the last of the milk and lemon juice, mix thoroughly.
Fold the egg whites into the batter, do not over mix the batter.
Fold the blueberries into the batter.
Divide the batter into 3 cake pans, bake for about 20-25 minutes or until baked.
Once baked, let it cool on a cooling rack.