Preparation:
Peel, pit and mash avocadoes in medium bowl. Add lemon juice, salt and pepper. In separate bowl, combine sour cream, mayonnaise, and taco seasoning. To assemble, spread bean dip on a large, shallow platter. Top with avocado mixture. Put on sour cream and taco mixture. Sprinkle with chopped onions, tomatoes, and olives. Cover with shredded cheese.