In a large bowl, add the butter, brown sugar and white sugar and mix well until you get an even mass.
Add the egg and mix well again.
Add the rest of the ingredients: flour, oats, raisins, baking powder, vanilla sugar, cinnamon and salt. Mix well.
Preheat the oven to 350 ℉ (180 ℃) with convection (fan).
Put baking paper on a baking tray. Form the cookies using a cookie dough or ice-cream scoop. If you don't have one, just try to make them all in similar size so they bake evenly. Place the cookies on the tray, making sure to leave some space between them. If you follow the amounts in this recipe, you should get around 14 cookies.
Bake the cookies for around 15 minutes and take them out of the oven. Done!
Notes
You can replace the raisins with pieces of chocolate, chocolate chips, dried fruit, or anything you wish.