Portabello mushrooms (2 each depending on size)
1/2 tsp butter per mushroom
1 slice toast per person
salt

Clean the mushrooms and remove the stem.  Heat a large frying pan (with no butter or oil) until very hot. 

Place a small piece of butter inside each mushroom, with a pinch of salt, then place in the pan, butter side up.  Cook until the butter begins to boil and the mushrooms are tender and juicy.  Serve on hot buttered toast.