Fettucine with Mustard Sauce

This idea appears in Patricia Wells's Paris Cookbook; she calls it the "French touch" with pasta.  She suggests the addition of cubes of bacon, ham, or mushrooms and says it's too rich for a main dish.

The very sharp, fresh-from-the-spout Maille mustard au vin blanc we brought back from Paris requires just under a teaspoon for the quantity of sauce.

• 2/3 cup heavy cream
• 1 egg yolk
• 1 1/2 Tbsp Dijon (or other good) mustard
• 3 Tbsp Parmigiano-Reggiano, grated
• sea salt and pepper

• fresh fettucine (1 jumbo egg)

• 2 Tbsp chives, minced
• Parmigiano-Reggiano, grated 

1. Heat cream, yolk, and mustard in large frying pan; simmer briefly.  Ad cooked fettucine and Parmigiano; stir to coat.  Permit to rest for 2 minutes.
2. Plate (dégustation plates); add chives and cheese and serve.