I do it every time, since I learned this method! The most delicious cake recipe.

Preheat the oven and prepare the pan:
Preheat the oven to 180°C and prepare a cake pan (29cm x 33cm / about 11.4 x 13 inches).
Butter and sugar mixture:
In a bowl, mix together the butter, icing sugar and vanilla sugar.
Adding the eggs and milk:
Add the eggs one at a time, mixing well after each addition. Then add the buttermilk.
Incorporating the dry ingredients:
Gradually add the flour, baking powder, and lemon zest to the mixture. Mix until you get a homogeneous dough.
Adding the blueberries:
Gently fold the blueberries into the batter.
Baking:
Pour the batter into the prepared pan and spread it evenly.
Bake in the preheated oven for about 30 minutes until golden brown.
Preparation of the frosting:
In a separate bowl, mix the butter, cream cheese, icing sugar and lemon juice until smooth.
Frosting and refrigeration:
Spread frosting evenly over cooled cake.
Refrigerate the cake so the frosting sets.
Tip:
Serve this delicious blueberry cake on a special occasion to treat your loved ones!