heat the oven to 170 degree Celsius.
melt the butter in a pan. Don't heat it too much, It just has to melt.
mix the light brown sugar with the vanilla sugar.
mix the melted butter with the sugar mixture. mix until the sugar starts to melt.
mix the egg to the butter sugar mixture.
Add the flower, baking soda and salt to the sugar,butter,egg-mixture. Do this with a spatula.
wait a few minutes untill the mixture is a bit cooler.
mix the chocolate chips in the mixture
make around the 15-20 small balls with the mixture.
put it in the oven for about 13 minutes. make sure jou check sometimes.