Cook the spaghetti according to package instructions. Drain and set aside.
In a large pan, cook the diced bacon until crispy. Remove from the pan and set aside on a plate.
In the same pan, cook the chicken breasts until browned on both sides, about 4-5 minutes per side. Remove from the pan and set aside.
Using the same pan, sauté the onion and garlic until soft and translucent, about 2-3 minutes.
In a separate bowl, whisk together the heavy cream, Parmesan cheese, Pecorino Romano cheese, and egg yolks.
Cut the cooked chicken into bite-sized pieces and return it to the pan with the onions and garlic.
Pour the cream mixture over the chicken and stir to fully combine.
Add the cooked spaghetti to the pan and toss until evenly coated in the sauce.
Mix in the crispy bacon and stir well.
Season with salt and pepper to taste, and serve hot.
