Cook the Pappardelle: Bring a large pot of salted water to a rolling boil. Add the pappardelle pasta and cook according to the package instructions until al dente, usually about 8-10 minutes. Reserve 1 cup of the starchy pasta water before draining the pasta.
Sauté Aromatics: In a large skillet, heat the olive oil over medium heat until shimmering. Add the finely chopped onion and sauté for about 5 minutes, or until the onion is translucent and soft.
Add Garlic and Spice: Introduce the minced garlic and red pepper flakes to the skillet. Continue to cook for an additional 1-2 minutes, stirring frequently, until the garlic is fragrant and golden but not burnt.
Incorporate Cream and Tomatoes: Carefully pour in the heavy cream while stirring to combine. Add the halved cherry tomatoes next, and allow the mixture to simmer for about 5 minutes, ensuring to stir occasionally. This will help the sauce thicken slightly and the tomatoes to soften.
Mix Pasta and Cheese: Add the drained pappardelle to the skillet, seasoning with salt and pepper to taste. Stir in the grated Pecorino Romano cheese, mixing thoroughly until the pasta is well-coated. If the sauce seems too thick, gradually add in the reserved pasta water a bit at a time until the desired creamy consistency is achieved.
Finish with Flavor: Stir in the lemon zest to brighten the dish and enhance the flavors. Taste and adjust the seasoning with additional salt and pepper, if necessary.
Serve: Serve the pappardelle in warmed bowls, garnishing each plate with fresh basil leaves. For an extra touch, sprinkle more grated Pecorino Romano on top.
Notes
For a visually appealing plate, drizzle a little olive oil and add a lemon wedge on the side.