- ½ cup walnuts
- Kosher salt
- ½ cup fresh ricotta
- Zest of 1 lemon
- 1 garlic clove, finely grated
- 2 tsp. finely chopped oregano
- 2 oz. Parmesan, finely grated, plus more for serving
- ¼ cup extra-virgin olive oil
- Freshly ground black pepper
- 1 lb. tube- or rod-shaped pasta (such as rigatoni or spaghetti)
1-Preheat oven to 350°F. Toast walnuts on a rimmed baking sheet, tossing once, until golden brown, 6–8 minutes. Let cool, then finely chop. Bring a large pot of generously salted water to a boil.
2-Vigorously mix walnuts, ricotta, lemon zest, garlic, oregano, and 2 oz. Parmesan in a large bowl until well combined. Add oil 1 Tbsp. or so at a time, stirring well after each addition, until all the oil is incorporated. Season pesto with salt and pepper.
3-Cook pasta in pot of boiling water, stirring occasionally, until al dente. Scoop 1 cup pasta cooking liquid into bowl with pesto and stir gently to combine (it’s okay if some of the pesto is still in small clumps). Using a spider, tongs, or slotted spoon, transfer pasta directly to bowl with pesto. Mix energetically until pesto thickens enough to lightly coat pasta, about 2 minutes; the pasta should have sauce clinging to it but there should also be some extra sauce that collects in bottom of bowl.
4-Divide pasta among bowls and serve with more Parmesan alongside for sprinkling over.