Blueberry Muffins

Preparation

1. Preheat an oven to 320° F (conventional oven).
2. Whisk the butter, one half of the sugar, salt and vanilla sugar until fluffy. Add the egg yolks individually and mix well. Add the vegetable oil.
3. Whisk the egg whites with the remaining sugar and salt until stiff.
4. Mix the flour and baking powder together and sift into the butter mixture. Add the stiff egg whites and carefully mix everything together.
5. Carefully fold in the blueberries.
6. Place paper cases into a muffin form and spoon the mixture into each case. Bake in the hot oven for approx. 25-30 minutes.