Cook them slowly in butter, not oil. And make sure the blade on the slice thing is as thin as possible. Once the underneath starts to solidify, gently fold one half over the filling, then the other half. It will cook itself from there, as in, you dont need to totally flip the whole thing over. Once done, slide it onto a plate from the frying pan.
As a nice addition, no matter what filling you use, chop some spring onions into it. You will have a lovely crunchy onion experience.
*I need to get back to the real world. Quickly*