These are always a big hit at parties. I add an egg into the mushroom/onion filling, to make them hold together a bit better. as they bake Also, I use minced green onions (with a few of the tops for color). Delish!
These are very good and great for parties. The convenience of being able to make them so far ahead is such a help. The flavor is deep and earthy and the puff pastry lends a buttery lightness.