Bring a large pot of water to a boil of high heat, season with salt.

Fry the bacon until crispy. Remove from the pan and set aside. Drain all but about 1 tablespoon of oil from the pan.

Add the pasta to the boiling water and slightly under-cooked. Reserve about 1/2 cup of the cooking water, and drain pasta.

Add the heavy cream to the pan with the bacon grease, and bring to a simmer over medium low heat.

Remove from heat and quickly whisk in the egg yolk.

Add the pasta and and stir to coat. Cook just a little longer until pasta is done (if it gets too thick add reserved pasta cooking water). Add pepper and season with salt to taste.

Stir in the Parmesan, bacon, and chives.

Place the pasta on the plate and spoon the sauce over. Top with more Parmesan cheese.