Pasta with Tomato, Onion and Butter
pasta, sauce, tomato
Source: Umami
Ingredients
- pound spaghetti
- Kosher salt and ground black pepper
- tablespoons salted butter, cut into 1-tablespoon pieces, divided
- small yellow onion, chopped
- ounce can tomato paste
- tablespoon balsamic vinegar OR white balsamic vinegar
- ounce Parmesan cheese, finely grated , plus more to serve
- Optional garnish: Chopped fresh basil