Gather the ingredients.
Heat 3 tablespoons olive oil in a large saucepan over medium heat. Add 1 large onion, finely chopped (about 2 cups), and cook until tender, about 7 minutes. Add 2 medium cloves minced garlic and cook until just fragrant.
Add 2 (28-ounce) cans crushed tomatoes in puree tomatoes, 3 tablespoons tomato paste, 1 teaspoon dried oregano, ½ teaspoon dried basil, and 1 pinch red pepper flakes, if using. Add ½ teaspoon salt, more to taste, and freshly ground black pepper to taste. Bring the sauce to a simmer.
Reduce heat to medium-low and simmer, uncovered, until the sauce thickens slightly, about 20 minutes. Adjust the seasoning with more salt and pepper, if desired.
Serve with your favorite pasta, and enjoy.
