Preheat oven to 350F
Sautee onions and ground beef in a skillet over medium heat, until onions are transparent and beef is brown. Remove excess fat.
Add taco seasoning and ¾ cup water and bring to a boil. Reduce heat and cook for 5 mins. Remove from heat and let cool
In a 9x13” baking dish, spread the refried beans evenly
Next, add a second layer of sour cream
Now add the cooled ground beef and onion mixture
Add the two cups of shredded Cheddar cheese
Bake uncovered for 15 minutes or until cheese is melted and bubbly
Top with the sliced olives and Fritos. Bake for 8 more minutes Remove from oven and top with diced tomatoes, chopped green onion, and lettuce (optional)