Reduce heat and simmer 5 minutes. Remove from heat and set aside. Brown beef and onions. Stir in sour cream, cheese and parsley flakes. Pour sauce onto plate.
Dip tortillas into sauce allowing sauce to cover both sides.
Place sauced tortilla onto greased oblong dish. Repeat until all mixture is gone. Pour remaining sauce over the top. Cook uncovered for 30 minutes in 350 degrees. Serve with cheese and sour cream.