Boil a large pot of water over high heat. Season the water generously with salt, and cook the pasta according to the manufacturers instructions.
1 pound pasta, kosher salt
Heat a large skillet over medium low heat. Add in the butter and garlic. Cook for 30-60 seconds until the garlic is fragrant.
3 tablespoons salted butter, 4 cloves of garlic
Pour in the heavy cream, milk and pesto. Stir and cook for 1 minute to warm through. Turn heat to low, then add in the parmesan cheese. Stir until it is melted.
2 cups heavy cream, 1 cup milk, 1/4 cup pesto, 2/3 cup grated parmesan cheese
Grab the cooked pasta with tongs out of the boiling water and add it directly to the sauce. Toss to combine. Add pasta water if the sauce needs to be thinned out.
Serve warm, garnished with parmesan cheese.
See the Recipe Notes below for more tips, FAQ's and ingredient substitutions.