Ingredients
Method
- Fill a large pot with water and bring it to a rolling boil over high heat. Season generously with salt, then add the penne. Cook according to package directions until al dente, typically about 1 minute less than the recommended time. Before draining, reserve 1/2 cup of the starchy pasta water.
- While the pasta cooks, warm the olive oil in a large skillet set over medium heat. Add the minced garlic and red pepper flakes, and sauté for about 1 minute until the garlic is fragrant but not browned.
- Pour the heavy cream and milk into the skillet. Bring the mixture to a gentle simmer, then let it cook for 2 to 3 minutes, stirring occasionally, until it begins to thicken slightly.
- Whisk in the grated Parmesan cheese until it is fully melted and the sauce is smooth. Season with salt and black pepper to taste, remembering that both the pesto and cheese add saltiness.
- Reduce the heat to low. Stir in the pesto and the reserved pasta water, mixing until the sauce is uniform and bright green.
- Add the cooked penne to the skillet. Toss the pasta thoroughly until every piece is evenly coated in the thick, creamy sauce. Serve immediately while hot.
Nutrition
Notes
For the best flavor, use freshly grated Parmesan from a block; pre-shredded cheese can make the sauce grainy. Don't overcook the garlic—if it turns brown, it will add a bitter taste to the sauce. Always stir the pesto in at the very end over low heat to preserve its vibrant green color and fresh basil flavor. The reserved pasta water is key: its starch helps bind the oily pesto and creamy sauce together. If the sauce gets too thick, add a splash more pasta water to loosen it. This pasta is best served right away, but leftovers can be stored in an airtight container in the fridge for up to 2 days—reheat gently with a splash of milk. For a lighter version, swap half the heavy cream for half-and-half.