Penne with Yellow Peppers and Sweet Onion

In large saucepot, prepare pasta in boiling salted water as label directs. Meanwhile, in 12-inch skillet, heat olive oil over medium heat until hot. Add yellow peppers, onion, black pepper, and 1/2 teaspoon salt and cook until vegetables are tender and golden, about 15 minutes, stirring frequently. Remove skillet from heat; stir in balsamic vinegar and chopped basil. When pasta has cooked to desired doneness, remove 1/2 cup pasta cooking water. Drain pasta and return to saucepot. Add yellow-pepper mixture and reserved pasta cooking water; toss well.