I have used cottage cheese and quark but I prefer quark as it's smoother.
I beat it really well with the eggs - I use a tub of quark with six eggs, and used like this the quark has never "split" for me.
I do season quite well with salt, pepper and mixed herbs.
I use any veg on hand, mushrooms, tomatoes and bacon or ham.
It really tastes yum and I can never make (or eat) enough!!