Take out of the oven as soon as the cheese has fully melted and is lightly browned on the top.
Serve immediately, with a good green salad if possible.
Remarks
You can replace the Espoisse with another kind of cheese. I prefer one that is both soft and well-flavoured (Saint Nectaire, Saint Marcellin, Mont d'Or...) but it's just as good with Comté or Cheddar.
And to drink?
Legend has it that Espoisse was Napoleon's favourite cheese, and he apparently liked to wash it down with a Gevrey-Chambertin. So, open a bottle of this and you'll dine like an emperor.