Heat olive oil in a large pot.
Add chopped onion. Cook until soft.
Add ground beef. Brown it fully.
Stir in minced garlic. Cook briefly.
Drain excess fat carefully.
Add crushed tomatoes and tomato sauce.
Stir in tomato paste thoroughly.
Add salt and black pepper.
Mix in basil and oregano.
Add sugar and red pepper flakes.
Reduce heat to low.
Simmer uncovered for one hour.
Stir occasionally to prevent sticking.
Add fresh parsley before serving.