In a large frying pan over medium heat, heat the olive oil. Once hot, add the onion, reduce the heat to low, and sweat for 20 minutes.

Meanwhile, whisk together the egg, extra yolks, nutmeg, and cheese, season with black pepper, and set aside.

Fry the garlic for 1 minute in the pan. Then add the artichokes, cover with a lid, and heat gently while the spaghetti cooks.

Boil the spaghetti in salted water according to package directions, or until tender. Scoop out a mug of cooking water and drain.

Remove the frying pan from the heat and add the spaghetti right away. Toss in the sauce, followed by the egg and cheese mixture. Working quickly, toss the pasta in the mixture, being careful not to let the eggs settle on the bottom of the pan (they may scramble). Once the pasta is coated, if necessary, add a little of the reserved cooking water to make a glossy sauce.

Top with additional Parmesan and black pepper to serve.