This is the recipe I am making for Saturday. I was thinking of making the filling ahead and then stuffing them just before baking. (Is this your recipe, Sharon/Chase? I can't remember where I got it.)

Spinach Filled Mushrooms

16-20 small mushrooms, wiped & trimmed
1c finely chopped onion
3T butter
10 oz pkg frozen spinach, drained & squeezed
1/2 c grated swiss cheese
Grated parmesan

Preheat oven to 300F. Butter shallow baking dish large enough to hold mushroom caps in one layer. Remove stems from mushrooms. Chop stems fine and saut� in butter with onion about 5 minutes or until onion is tender. Add spinach and stir to mix thoroughly. Add swiss cheese, stir lightly. Remove from heat.

Fill caps with spinach mixture. Sprinkle with parmesan and arrange in prepared pan. Bake, uncovered 15-20 minutes. Serve warm.

My notes: use a little more swiss cheese than called for.

This is Sharon's recipe. It is simple to make and is delicious. My favourite stuffed mushroom.

I've never made it advance, but I don't see why you couldn't.

Home Cookin Chapter: Recipes From Thibeault's Table

Stuffed Mushrooms
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Posted by: chase (My Page) on Wed, Apr 13, 05 at 19:57
I don't know if this is inventive, actually they are so simple but they are d@mn good.
Stuffed Mushrooms
20 large white mushrooms
1/3 cup butter (maybe a bit more)
4 or 5 green onions chopped fine
2-1/2 cups grated cheddar
1/3 cup bread crumbs more or less if needed
Salt
Clean mushrooms and carefully remove stems. Chop stems and onions finely (I use the food processor). Melt butter in a saute pan. Saute mushroom stems and onions over medium heat until soft but not browned and the stems have given up their juices. Mixture should be quite moist. Add the bread crumbs, only enough to absorb the liquid. Add the grated cheese and stir just until it has melted. Don't worry if the oil separates from the cheese.~
Stuff the mixture into the caps and sprinkle with a bit of salt (or you can salt after they come out of the oven...which is what I usually do).
Bake at 375 for 12-15 minutes or until the caps are nice and soft.

Here's a recipe I like....and they are no good made ahead....the salt in the cheese makes the mushrooms weep, and they get watery and the filling soggy.
Best to make the filling and stuff at the last minute.

1 pound fresh mushrooms ( meduim size)
1/4 c. butter
3 green onions
1/2 c finely grated fresh bread crumbs
3 T crumbled Maytag Blue Cheese
1 T minced fresh parsley
1T lemon juice
1/2 t salt
Wipe mushrooms and remove stems. Chop stems and green onions ( tops too!) and saute in the butter until just getting soft. Add crumbs, cheese, parsley, lemon juice and salt. Place in mushroom caps in a shallow baking dish, sprinkle with paprika, Bake 8 minutes at 450, and watch them disappear.

Linda C

Thanks for the advice. I'll make the filling ahead and stuff at the last minute.

I have found that if I parcook the unstuffed mushroom caps for about a minute or two in a covered dish in the microwave (removed stem sides up), it extracts enough juice to keep the filling from becoming soggy when they're baked. I save the juice to put in the bottom of the baking pan or use in gravy or soup.