Preheat oven to 400. Rinse, pat dry and finely chop mushrooms (makes about 5 cups); set aside. In a large saucepan melt butter. Add onion and celery; saute until tender, about 5 minutes; set aside.
In a large mixing bowl beat eggs and cream cheese until smooth. Add bread crumbs, salt, basil, rosemary, oregano, black pepper and reserved onion and celery mixture and mushrooms. Stir until mixture is well blended and smooth. Butter a 7 x 4 x 2 inch loaf pan.
Cover the long side and bottom of pan with a strip of waxed paper leaving a 1-1/2 inch overhang. Spoon mushroom mixture evenly into pan. Cover top of pan with foil. Bake until firm, about 1-1/2 hours.
Cool in pan until lukewarm. Remove from pan using waxed paper overhang as an aid; discard paper.
Serve at room temperature with crackers as an appetizer garnished with mushroom slices, grated carrot and chopped onion, if desired. Yield: 12 to 14 portions.