Fill a stockpot with 6 quarts of water, cover and bring to a boil. In a large skillet, combine olive oil, garlic, pancetta and red pepper flakes, cook over high heat until garlic is golden. Add chicken stock and bring to a boil. Lower the heat to medium and boil gently until the liquid is reduced by half, about 6 minutes. Add butter, stirring until melted.

Meanwhile, add linguine to boiling water. Cover partially until the water just returns to a boil, then uncover, stir the pasta and cook until barely al dente. Drain pasta, reserving 1/4 cup of the pasta water.

Add linguine to skillet and cook over moderate heat, tossing occasionally, until coated with sauce. If linguine