Mushrooms Jambalaya

1 pound large, fresh mushrooms
2 tablespoons butter
1/2 cup finely chopped yellow onion
1/2 cup finely diced pepperoni
1/4 cup finely chopped green pepper
1/4 teaspoon garlic, pressed
2 cups crushed Ritz cracker crumbs
3 tablespoons grated Parmesan cheese
1 tablespoon chopped parsley
1/2 teaspoon seasoned salt
1/4 teaspoon oregano
1/8 teaspoon pepper
1 cup chicken broth

Preheat oven to 325 degrees F.

Wash mushrooms and drain; remove stems and chop. Melt butter in a skillet; add onion and saut