Tomato paste, red onion, and fresh basil add a hint of sweetness to this quick-cooking marinara. Pile our meatballs on spaghetti and you have a familiar favorite.
Heat oil in a medium saucepan over medium heat. Cook onion and garlic, stirring occasionally, until tender, about 5 minutes. Stir in tomato paste.
Add pureed tomatoes, basil, oregano, red-pepper flakes, and 1/2 teaspoon salt. Season with pepper, and bring to a simmer. Reduce heat, and gently simmer, stirring occasionally, until sauce is thick, 25 to 30 minutes.
Sauce can be frozen for up to 1 month.