Bacon and swiss chard pasta

1 pound linguine
12 ounces bacon, cut crosswise into 1/2-inch slices
1 very large red onion, halved, sliced (about 6 cups)
2 large bunches Swiss chard, stemmed, chopped (about 12 cups)
1 tablespoon balsamic vinegar
3 tablespoons extra-virgin olive oil
2/3 cup grated Parmesan cheese

Cook linguine in large pot of boiling salted water until tender but still firm to bite, stirring occasionally. Drain, reserving 1 cup pasta cooking liquid.

Meanwhile, cook bacon in heavy large pot over medium heat until beginning to crisp, about 10 minutes. Transfer to paper towels to drain. Drain all but 2 tablespoons bacon drippings from skillet. Add onion and sauté over medium-high heat until softened, about 7 minutes. Add Swiss chard and sprinkle with salt and pepper. Add pasta cooking liquid to skillet. Toss until chard is wilted and tender, about 4 minutes. Sprinkle vinegar over; cook 1 minute.

Add linguine and oil to sauce in pot and toss to coat. Transfer to large bowl. Sprinkle with bacon and cheese. Season to taste with salt and pepper.

From Bon Appetit May 2008