Put the flour and a pinch of salt into a large bowl.
Make a well in the center of the flour, pour the oil into the well and add the egg yolks and beer.
Working from the center out-ward,whisk just long enough to produce a smooth batter.
Let the batter stand in a warm place for at least one hour.
Just before using the batter, beat the egg whites to stiff peaks and fold them gently into it.