Spaghetti with Tomato and Walnut Pesto
2/3 cup walnuts
2 pints cherry tomatoes, halved
2 tablespoons plus 1/3 cup olive oil, plus more for drizzling
6 oil-packed anchovies, coarsely chopped
2 garlic cloves, coarsely chopped
1 teaspoon finely grated lemon zest
1/4 teaspoon crushed red pepper flakes
1/2 ounce Parmesan, finely grated (about 1/2 cup), plus more for serving
1 teaspoon freshly ground black pepper
12 ounces spaghetti
1/2 cup (packed) basil leaves
Preheat oven to 350Â°F. Toast walnuts on a rimmed baking sheet, tossing once, until slightly darkened, 8â10 minutes. Let cool.
Heat broiler. Toss tomatoes with 2 Tbsp. oil on a rimmed baking sheet; season with salt. Broil, tossing once, until tomatoes are blistered and have released some of their liquid, 5â7 minutes. Let cool.
Pulse anchovies, garlic, lemon zest, red pepper flakes, and 1/2 oz. Parmesan in a food processor until finely ground. Add walnuts and half of tomatoes, then, with motor running, stream in 1/3 cup oil; process just until combined. Season with salt. Transfer pesto to a large bowl and stir in black pepper.
Cook pasta in a large pot of boiling salted water, stirring occasionally, until al dente. Drain, reserving 1/2 cup pasta cooking liquid.
Transfer pasta to bowl with pesto and add a splash of pasta cooking liquid. Toss, adding more cooking liquid as needed, until sauce coats pasta. Add basil and remaining tomatoes.
Divide among bowls; top with more Parmesan and black pepper and drizzle with oil.
Pesto can be made 1 day ahead. Cover and chill.