Keto Creamy Lemon Spaghetti
Bright and buttery Italian pasta dish that comes together in minutes. Fresh lemon juice and zest combine with Parmigiano-Reggiano to create a silky emulsified sauce that coats each strand of spaghetti. The key is using starchy pasta water to build a glossy glaze. Serve immediately as a light weeknight dinner or elegant starter. This version relies on classical Italian technique rather than cream, letting citrus and cheese shine.
Ingredients
- 16 ounce spaghetti, dried
- 3 tablespoon unsalted butter
- 3 tablespoon extra-virgin olive oil
- 1 lemon, zest and juice
- 2 clove garlic, minced
- 1 cup Parmigiano-Reggiano, gratedPecorino Romano1:1sharp/saltyeggs-free
aged hard cheeses work
- salt, to taste
- pepper, to taste
Instructions
- 1
Cook spaghetti al dente according to package directions.
- 2
Drain pasta, reserving 1 cup cooking water.
- 3
Heat butter and olive oil in a large pan, then cook garlic and lemon zest until fragrant, about 1 minute.
- 4
Add spaghetti to the lemon butter mixture and stir in 1/2 cup cooking water.
- 5
Toss continuously for 2 to 3 minutes until sauce appears shiny and glazed, adding more cooking water if dry.
- 6
Remove from heat, add lemon juice, and sprinkle cheese over pasta.
- 7
Toss until cheese and juice emulsify into smooth sauce.
- 8
Season with salt, pepper, and additional lemon juice to taste.
- 9
Serve immediately, optionally topped with extra cheese, lemon zest, or parsley.
Tips
Reserve pasta water before draining. The starch is essential for emulsifying the sauce instead of using cream.
Keep heat moderate when combining cheese and juice to prevent clumping. Off-heat emulsification works best.
Serve immediately. This dish doesn't hold well as the sauce sets and becomes heavy as it cools.
Good to Know
Best enjoyed immediately. Leftovers can be refrigerated up to 2 days but texture degrades. Reheat gently with splash of water and lemon juice.
Zest lemon and mince garlic up to 1 day ahead. Cook pasta up to 2 hours ahead and toss with olive oil to prevent sticking. Final assembly must be done fresh.
Serve in warm bowls immediately. Offer extra grated cheese, fresh lemon zest, cracked pepper, and fresh parsley on the side. Pairs well with dry white wine and simple green salad.
Common Mistakes
Overcook pasta to avoid mushy texture that prevents proper sauce coating
Use low heat when combining cheese to avoid grainy, separated sauce
Don't skip pasta water as it contains essential starch for proper emulsification
Substitutions
Dairy-Free Swaps
General Alternatives
FAQ
Can I make this dish ahead of time?
Cook pasta and prep ingredients ahead, but assemble the final dish only when ready to eat. The sauce will thicken and separate as it sits. You can reheat leftover spaghetti gently with a splash of water and lemon juice, though texture will suffer.
What if my sauce looks broken or grainy?
Remove from heat and whisk in additional pasta water one tablespoon at a time until smooth. Keep temperature low when adding cheese and juice. The emulsion depends on gentle heat and continuous tossing.
How long can I keep leftovers?
Store covered in the refrigerator for up to 2 days. The sauce will thicken significantly. Reheat gently over low heat with additional water and fresh lemon juice to restore glossy texture.