Why It Works
- Using the starchy pasta water to emulsify the sauce creates a cleaner flavor than you'll find in renditions of this dish made with cream.
- Cooking the pasta in a smaller volume of water than the frequently recommended "large pot" produces starchier water, which helps to better emulsify the sauce.
Lemon zest and juice perk up this classic buttery and cheesy pasta dish. The secret lies in emulsifying the sauce to a satiny consistency using the starchy pasta water, not cream.
- 5 tablespoons (70g) unsalted butter
- Finely grated zest of 1 lemon, plus fresh juice to taste and additional grated zest for serving
- 1 medium clove garlic, minced
- Kosher salt
- 1 pound (450g) fresh spaghetti
- 1 ounce (30g) grated Parmigiano-Reggiano cheese, plus more for serving
- Freshly ground black pepper
In a large skillet, melt butter over medium heat until foaming. Lower heat to low, add lemon zest and garlic, and cook, stirring, until fragrant, 1 to 2 minutes.
Meanwhile, in a medium pot of boiling salted water, cook pasta until just shy of al dente. Reserve about 1 cup (240ml) of the starchy pasta water, then drain pasta.
Add pasta to butter mixture, along with 1/2 cup (120ml) reserved pasta water. Increase heat to medium-high and cook, stirring and tossing to coat, until pasta is glazed in a satiny, emulsified sauce.
Add grated cheese and toss and stir rapidly until sauce thickens; if it becomes too tight and dry at any time, add more pasta-cooking water to loosen it sufficiently. Add lemon juice to taste, starting with 1 tablespoon (15ml), then adding more until desired tartness is reached. Season with salt and pepper.
Serve spaghetti right away, topping each serving with additional grated lemon zest and cheese.