Cheddar Stuffed Mushrooms

I got this from a recipe tree email. I haven't had a chance to try it yet, but it's up there on my appetizers to try list!!

Preheat oven to 350.

Remove stemps from mushrooms and chop stems.

Melt butter.

With a pastry brush , gently brush mushroom caps all over with some melted butter.

Arrange caps , stemmed sides up , on a large baking sheet.

Lightly toast walnuts and finely chop.

Finely chopped parsley.

Saute onion with chopped stems in remaining butter over modestly high heat until mixture is softened.

Remove skillet from heat and stir in remaining ingredients.

Divide mixture among caps , mounding it slightly.

Mushrooms may be stuffed 4 hours ahead and chilled , covered.

Bake mushrooms in middle of oven for 20 minutes.

Serve warm.

mushroom, unsalted butter, walnuts, fresh parsley leaves, onion, sharp cheddar cheese, fresh breadcrumb, salt