Can I make this ahead?
This dish is best served fresh, but you can prepare the sauce components (zest, juice, sliced garlic) ahead. Cook and sauce the pasta just before serving to avoid it becoming gummy.
What can I substitute for heavy cream?
Use half-and-half, whole milk mixed with a little butter, or crème fraîche. Adjust the amount slightly since lighter options may need extra pasta water to achieve the same silky consistency.
Why is my sauce breaking or looking separated?
Keep heat moderate throughout cooking and reserve pasta water before draining. Add pasta water slowly while stirring to emulsify the cream and oil; this creates a stable, creamy sauce.
Can I scale this recipe up?
Yes. Scale all ingredients proportionally, but add pasta water gradually since larger batches may need less liquid relative to the sauce volume.
How much Parmesan should I add?
Grate fresh Parmesan over the finished bowl to taste—typically 2–3 tablespoons per serving. Add it at the table so it doesn't clump or become grainy in the warm sauce.