For arugula purée
2 tablespoons pine nuts, lightly toasted and cooled
5 oz baby arugula, coarsely chopped (7 cups)
1/2 cup extra-virgin olive oil
1/2 oz finely grated Pecorino Romano
1 teaspoon salt
For cherry-tomato sauce
3 tablespoons extra-virgin olive oil
2 garlic cloves, crushed with side of a large knife
1 1/2 lb cherry tomatoes (about 5 cups), trimmed if necessary
3/4 teaspoon salt
1 lb dried fettuccine (not made with egg)
Accompaniment: grated Pecorino Romano
Pulse pine nuts in a food processor until finely ground (be careful not to grind to a paste). Add arugula, oil, cheese, and salt and pulse until almost smooth.
Make tomato sauce:
Heat oil in a 12-inch heavy skillet over moderate heat until hot but not smoking, then cook garlic, stirring, until golden, about 2 minutes. Discard garlic. Add tomatoes and salt and cook, stirring occasionally, until tomatoes are collapsed but not falling apart, 15 to 20 minutes.
Cook and serve pasta:
Cook fettuccine in a 6- to 8-quart pot of boiling salted water until al dente. Drain pasta in a colander and return to pot. Add arugula purée and toss until well coated. Transfer to a platter or plates and top with tomato sauce.