It just occurred to me that I recently made some super good stuffed mushrooms.
They were based on the recipe here:
https://jamiegeller.com/recipes/isra...kets-bourekas/
"Spanish" onions are generally just yellow onions here. Any will do, pick whatever you like (I used a red). Cremini mushrooms are the small brown baby portabellos. Standard white or any other mushroom is fine.
But I found that the recipe made about twice as much filling as I used. I told the story here:
What to make for . . . ?
When I used the extra filling, I did indeed use some extra large portabello caps. Since they were for the hubby I swished them with Worcestershire sauce and mixed in some parmesan cheese as well as cheese on the top.