Here are the main points to watch if you want to make a successful soufflé: :
- The roux must not be allowed to brown (don't overcook it)
- The mixture must not be too hot when you add the egg yolks (or they will cook)
- The whites must be beaten until they are quite stiff
- The dish should be buttered well, then dusted with flour
- The dish should have sloping sides (to allow the soufflé to swell and rise during cooking)
For a professional touch you can give the soufflé a flat, smooth top by smoothing the surface with a palette-knife
before baking and begin the cooking with 3 minutes under the grill.
As for the cheese, I prefer Comté, but you can use whatever you choose, even a mixture.