bacon-cheese stuffed shells

Ingredients

• 24 - uncooked jumbo pasta shells
• 1 cup chopped fresh mushrooms
• 1 cup finely chopped onion
• 1 tablespoon plus 1/4 cup of butter, divided
• 1 1/2 cups ricotta cheese
• 1 package 8 oz cream cheese, softened, divided
• 1 1/2 cups shredded asiago cheese, divided
• 1 cup shredded parmesan cheese
• 1 cup crumbled cooked bacon
• 2 tablespoons minced fresh parsley, divided
• 1/2 teaspoon garlic salt
• 1/2 teaspoon ground nutmeg
• 1/4 teaspoon pepper
• 2 tablespoons all purpose flour
• 2 cups heavy whipping cream
• 1/2 cup chicken broth
• 1/2 cup 2% milk
• 2 cups shredded romano cheese
• 1 1/2 cups shredded part-skim mozzarella cheese