Pasta with Chard and Basil

In a large pot, cook pasta in salted boiling water according to package directions; drain, reserving 3/4 cup pasta cooking water. Return pasta to pot; cover to keep warm.

Meanwhile, in a very large skillet heat olive oil over medium-high heat. Add Swiss chard stems, garlic and salt. Cook and stir for 2 minutes. Add the tomato paste. Cook and stir for 1 minute more. Gradually whisk in 1/2 cup of the pasta cooking water until smooth. Bring to a simmer. Add cooked pasta, chard leaves, basil and vinegar to sauce; stir to combine. If desired, stir in up to 1/4 cup additional cooking liquid to reach desired consistency. Season with black pepper. Divide among serving dishes. Sprinkle with cheese and additional pepper, if desired.