Preheat oven to 350º F/ 180º C. Line two 7 inch/ 18 cm cake pans with circles of parchment paper. Grease very well the the pans inside.
Sift the flour with the baking powder in a medium bowl. Set aside.
Divide the eggs into two large bowls.
Whip the egg whites with an electric mixer until thick and foamy.
Add the sugar and vanilla to the yolks. Beat with the electric mixer for 3-4 minutes, until the mixture becomes thick and pale.
Using a rubber spatula gradually add the flour mixture to the yolks. When the batter starts thickening, start adding from the egg whites. Fold gently the batter, to make sure all flour and whites are dissolved and distributed well around.
Divide the batter between the two pans. Bake for about 35 minutes or until a toothpick inserted in the centre comes out clean.
Let the cakes cool in the pans for 15 minutes and then very carefully run a knife around the edges. Remove the cakes from the pans and let them cool until room temperature.
Ideally, if your timing allows, refrigerate them for 4-6 hours or overnight, wrapped in cling film.
Whipped Cream Frosting
Pour the cream in a large mixing bowl (refrigerated in advance at least 6 hours). Add powdered sugar and vanilla. Whip them until soft peaks form.
Wash and dry the blueberries, if you are using them.
Cut horizontally each cake base into two equal parts. Place one layer on a cake stand or a serving plate. Generously spread frosting on top (2-3 tablespoon). Sprinkle some blueberries.
Continue the process until stacking all four layers.
Spread the remaining frosting around the cake. Decorate with blueberries or leave plain.
Refrigerate the cake for 4-6 hours before serving it.
Store the cake 2-3 days in the fridge.
Instead of blueberries you can use other berries or just skip them.
Instead of vanilla extract you can use lemon flavour and make a Light Lemon Cake.