Begin by bringing a large pot of water to a boil. Generously season the water with salt.
In a wide skillet add the heavy cream and pesto. Stir together and heat over medium high heat until the cream begins to bubble. Add the parmesan cheese and stir until melted. Taste the cream sauce and check if it needs some salt. Depending on the seasoning of the pesto and parmesan it may not need much salt. Add kosher salt and pepper to your taste. Turn down the heat to low and let simmer while the gnocchi cook.
When the water is boiling add the gnocchi. Gently stir the gnocchi to prevent sticking. Cook for 3-5 minutes or until the gnocchi float. Once the gnocchi float allow them to cook for another minute. Use a slotted spoon to lift the gnocchi out of the water and transfer directly into the skillet with the cream sauce.
Cook the gnocchi in the cream sauce for another couple of minutes until the sauce has thickened slightly, stirring gently. Taste and check for seasoning and it's ready. Serve with extra parmesan cheese if desired.