Cook pasta in a large pot of boiling salted water until al dente; drain well and return to pot or large mixing bowl.

Combine basil, parmesan, pine nuts, garlic, kosher salt and pepper into a food processor. Pour olive oil in as it blends for about a minute or so; using more if needed.

Melt butter in a saucepan on medium heat. Once melted, add heavy cream and a dash of nutmeg. Stir well and reduce heat to low. Allow to simmer for 5 minutes.

Add the pesto into cream sauce and stir well. Pour the creamy pesto sauce over the pasta and stir to coat evenly.

Serve immediately, garnish with parmesan and parsley, if desired.