Bring a large pot of water to a boil, add a pinch of sea salt, and cook the whole wheat spaghetti until al dente.
While the pasta cooks, dice the chicken breast and pancetta into small, bite-sized pieces.
In a large skillet over medium heat, cook the pancetta until the fat renders and it becomes crispy.
Add the diced chicken to the skillet with the pancetta and sauté until the chicken is golden brown and cooked through.
Stir in the minced garlic and baby spinach, cooking for about 1 minute until the spinach is just wilted.
In a small bowl, whisk together the whole egg, egg yolk, grated parmesan cheese, and black pepper until well combined.
Reserve 1/4 cup of the starchy pasta water, then drain the spaghetti.
Turn off the heat on the skillet and add the hot pasta directly to the chicken and pancetta mixture.
Pour the egg mixture over the pasta and quickly toss with tongs, adding the reserved pasta water a tablespoon at a time to create a creamy, glossy sauce.
Season with sea salt and serve immediately while the sauce is silky.