Recipe 1 pkg. (17.3 ounces) Pepperidge Farm® Puff Pastry Sheets, thawed 1/3 cup butter 2 stalks celery, sliced 3 medium onions, chopped (about 1 1/2 cups) 8 oz. mushrooms, sliced (about 3 cups) 1/3 cup all-purpose flour 3 1/4 cups Chicken Broth 1 tsp. dried thyme leaves, crushed or...