Spread refried beans on bottom of pie plate. Then spread the sour cream mixture over top. Layer with onions, tomatoes and black olives. Then cover with shredded cheese. Top with avocado if desired. Serve with Tortilla chips
(can be made ahead of time and keep in refrigerator until serving. Add avocado right before serving if using)
Recipe by One Green Fork at https://www.onegreenfork.com/layered-taco-dip/