1 pound penne pasta
6 ounces pancetta, cut in 1/4-inch cubes
1 to 2 tablespoons olive oil (optional)
2 onions, peeled and sliced in half-moons
1/4 teaspoon salt
2 garlic cloves, peeled and minced
1/2 teaspoon crushed red-pepper flakes
1 large head leafy escarole, sliced in wide ribbons
1/2 cup grated pecorino Romano cheese

Heat a large stockpot of well-salted water to a boil. Add the pasta and cook according to package directions until al dente.

Meanwhile, heat the pancetta in a large skillet or Dutch oven over medium-high heat; cook until fat is rendered. Add the oil, if needed. Add the onions and season with the salt. Cook, stirring, until completely soft, for 12 minutes. Add the garlic and cook for 1 minute. Sprinkle with the red-pepper flakes.

Drain pasta, reserving 1/2 cup cooking water. Return pasta to pot and stir in onion mixture and the escarole. If dish seems dry, stir in some reserved pasta water. Toss with the pecorino cheese.

Makes 4 servings.