I make this every time, ever since I learned this method! The most delicious cake recipe.

Ingredients:
250g butter (1.1 cups)
250g icing sugar (2 cups)
1 tbsp vanilla sugar
5 eggs
200ml buttermilk (0.85 cups)
500g all-purpose flour (4 cups)
3 tsp baking powder
Lemon zest
450g blueberries (3 cups)
Cooking instructions:
Preheat the oven and prepare the tin:
Preheat the oven to 180°C and prepare a cake tin (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.
Add the eggs and milk:
Add the eggs one at a time, mixing well after each addition. Then add the buttermilk.
Incorporate the dry ingredients:
Gradually add the flour, baking powder and lemon zest to the mixture. Mix until smooth.