I don't think cheese is necessary, I mentioned that you can put different fillings. I put cheese because pumpkin has a very distinct flavour and texture (I admit it's the first time I've had Butternut squash, otherwise mostly Hokkaido) and the mixture of young cheese (not sour cream) and leek tastes very good to me. I have some frozen chard in the fridge which would be just as good with cheese, I think.... maybe next time I'll make some pancakes with this filling :)