Get the Ingredients for this Recipe
Bring a large pot of generously salted water to a boil. Cook the pasta until al dente, reserving 1 cup of the pasta water before draining.
While the pasta cooks, heat the olive oil and butter in a large skillet over medium heat. Once the butter has melted, add the sliced garlic and cook for 1 to 2 minutes, just until fragrant and lightly golden. Do not let the garlic brown.
Stir in the pesto, then pour in the heavy cream or half-and-half. Stir until smooth and let the sauce warm through for 1 to 2 minutes over low heat.
Add the drained pasta and toss until well coated. If needed, add a splash of the reserved pasta water until the sauce reaches your desired consistency.
Turn off the heat completely. Add the grated Pecorino Romano or Parmigiano Reggiano and toss until the cheese has fully melted into the sauce, making it smooth and creamy.
Finish with freshly cracked black pepper and serve immediately with extra grated cheese on the side.