can the enamel surface develop a seasoning, or does it have to be well oiled every time?
@Huh?? , it does not really develop any seasoning.
I generally give it a cleaning once it has cooled down, but I don't get too thorough.
I have done mostly breakfasts on it and I start with bacon around the perimeter.
Then the grease slowly covers the surface.
I would definitely recommend using oil or something if you wanted to start out sautéing onions, and then progressing from there.