Ingredients
- 5 tablespoons (70 g) unsalted butter
- Finely grated zest of 1 lemon, plus fresh juice to taste and extra zest for serving
- 1 medium clove garlic, minced
- Kosher salt
- 1 lb (450 g) fresh spaghetti, store-bought or homemade
- 1 oz (30 g) grated Parmigiano-Reggiano, plus more for serving
- Freshly ground black pepper
Instructions
In a large skillet, melt the butter over medium heat until foaming. Lower the heat, add the lemon zest and garlic, and cook, stirring, until fragrant, 1–2 minutes.
Meanwhile, cook the pasta in a medium pot of boiling salted water until just shy of al dente. Reserve about 1 cup of the starchy pasta water, then drain.
Add the pasta to the butter mixture along with 1/2 cup of the reserved pasta water. Increase the heat to medium-high and cook, tossing to coat, until the pasta is glazed in a satiny, emulsified sauce.
Add the grated cheese and toss and stir rapidly until the sauce thickens; if it gets too tight and dry, add more pasta water to loosen. Add lemon juice to taste, starting with 1 tablespoon and adding more until the tartness is right. Season with salt and pepper.