Sorry this is brief, and rushed - have to dash out...

Have a look at the attached file.

After tracing half your parabolic curve ( using the freeform line with control points, in 'top view' with the 'points' turned on), I extruded half the height.

Then traced again quarter the oval outline shape of the dish, mirrored it and did a boolean diff. then mirrored it again to get the full height.

Maybe someone's else has another way...

- Hamish