I don't know how call GRATAN in English, according to my dictionary, it is showed as "au gratin".
Anyway, yesterday I tried to make perfect Toufu au gratin, it means that I used only Toufu to make white sauce.
Just I whipped TOUFU with a little powdered consomme.
And bake it in the oven.
Looks perfect. The taste is not so bad, it means -- it was a little TOUFU-ish.
So if you love TOUFU, the taste is wonderful, and you are not a lover of TOUFU, the taste is not so bad.
However it's really easier to make TOUFU cream instead of white sauce.
It might be better to add some soy milk or some cheese (if you don't mind too much calorie).