There is this Arab food channel I like to watch from time to time.
My favorite part is when they have these mini-recipe advertising a certain food product, and suggestions of how to cook using them.
The whole recipe-advert lasts maybe 60 seconds or less, but I really like them.
Life is in the details, so I've heard.
Anyways, I think I picked this recipe up from one of those adverts (maybe the butter product one), so it's really more of a method rather than a strict quantitative recipe approach.
It's really up to you how much cheese or mushroom you want in it; the concept is clear though.
I've also heard that this is called mushroom melts, rather than mushroom grilled cheese sandwich.
You can choose any cheese you favor, but I particularly recommend aged cheddar, or comte, or Gruyere.
onion, diced finely
Saute the onion and the mushroom in a bit of oil or butter until cooked; season to taste; set aside.
With two toast sliced in front of you, put cheese on both toasts.
Put a quantity of the cooked mushroom on one of the toasts.
Seal the sandwich , cheese side on the mushroom.
Lightly butter the outsides of both toasts.
Heat a pan on the stove, put the sandwich in.
When one side is golden-brown, carefully turn over to equally brown the other side.
Remove the sandwich from the pan, cut diagonally, and consume while still hot.
صحة و عافية