Bring a large pot of salted water to a boil and cook pasta according to package directions. Drain and reserve 1/4 cup pasta water.
Meanwhile, in a large skillet or pot, add the butter and melt over medium heat. Add the pesto and whisk until it begins to bubble.
Lower the heat to medium-low and slowly whisk in the milk or cream until it is incorporated. Add the cook pasta and toss to coat. If needed, use reserved pasta water to thin out sauce.
Plate pesto pasta and top with freshly grated parmesan cheese and toasted pine nuts (optional).
Note: Metric ingredient measurements are provided as a courtesy using a third-party calculator and are rounded to the nearest unit. The recipes provided on this site have not been tested with metric measurements and their accuracy cannot be verified.
The nutritional information provided is based on third-party calculations and is an estimate only. Accurate nutritional facts will vary based on the particular brands used, portion sizes, measurement accuracy and more.