Penne with Broccoli Rabe, Walnuts, and Pecorino

Preparation

1. Step 1

   Heat oil in heavy large skillet over medium-high heat. Add leeks and sauté until golden and soft, about 5 minutes. Add broccoli rabe and sauté, tossing with tongs, until slightly softened and bright green, about 3 minutes. Add garlic and stir 1 minute. Stir in broth, crme frache, and lemon peel, then 1/3 cup cheese.

   Step 2

   Season to taste with salt and pepper. Meanwhile, cook pasta in large pot of boiling salted water until just tender but still firm to bite, stirring occasionally. Drain, reserving 1 cup pasta cooking liquid. Return pasta to pot. Stir in broccoli rabe mixture and walnuts, adding 1/2 cup cooking liquid to moisten and adding more by tablespoonfuls if needed. Divide pasta among bowls. Serve, passing remaining cheese separately.

2. Step 3

   *An Italian leafy green vegetable with scattered clusters of tiny, broccoli-like florets; available at some supermarkets and at specialty foods stores.