Cook ground beef with onion and garlic until no pink remains. Drain any fat.
Add taco seasoning, salsa and 1/3 cup of water. Cook until thickened, about 5 minutes and remove from heat.
In a large bowl, combine beef mixture, sour cream, soup and 1 cup of cheese.
Slightly crush Doritos (not completely, you don’t want crumbs). Layer 1 1/2 cups Doritos in the bottom of a 2 qt casserole dish . Top with 1/2 of the beef mixture. Repeat layers. Finally top with an additional 1 to 1 1/2 cups Doritos and remaining cheese.
Spray a piece of foil with cooking spray and cover casserole.
Bake 30 minutes covered, remove foil and bake uncovered for an additional 20 minutes or until hot and bubbly. Top with lettuce, tomatoes and olives if desired.
Nutrition information provided is an estimate and will vary based on cooking methods and brands of ingredients used.Nutrition calculated without optional toppings.