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.
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.
- Yield:Serves 4
- Active time: 10 minutes
- Total time:15 minutes
- 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.