1. Make the gremolata: In a small bowl, combine the parsley with the garlic and lemon zest. Using a spatula or small spoon, mix until just combined and set aside. (You should have about ¼ cup.)

2. Make the spaghetti: Bring a large pot of salted water to a boil. Add the spaghetti and cook until al dente, according to the package instructions or about 8 minutes.

3. Meanwhile, in a large bowl, whisk the crème fraîche with the olive oil and lemon juice until combined. Add the Parmesan, red-pepper flakes and reserved gremolata; mix until combined.

4. When the spaghetti is cooked, use tongs to transfer it directly to the bowl with the sauce. Toss the spaghetti until the sauce coats the noodles evenly, adding pasta water 1 tablespoon at a time to thin the sauce if needed. Season to taste with salt and pepper.

5. Transfer the spaghetti to a large serving bowl or divide among four plates. Garnish the spaghetti with additional Parmesan, a drizzle of olive oil and the whole parsley leaves. Serve immediately.