Heat olive oil in a large saucepan over medium heat.

Add the flour and whisk until combined. Cook for 1-2 minutes, stirring constantly.

Add the onion and garlic and cook until softened, about 5 minutes.

Add the red pepper flakes, basil, oregano, parsley, salt, and black pepper and stir to combine.

Add the crushed tomatoes and water and bring to a simmer.

Reduce heat to low and simmer for 60 minutes, stirring occasionally.

Serve over spaghetti or your favorite pasta.