Instructions:
- Butterfly the chicken breasts horizontally if they are very thick. Season thoroughly with salt, pepper, and Italian herbs.
- Heat olive oil in a large, heavy-bottomed skillet over medium-high heat. Sear chicken for 5–7 minutes per side until golden brown and cooked through (internal temp 165°F / 74°C). Remove chicken, cover loosely with foil, and let rest. Keep the browned bits in the pan.
- Bring a large pot of salted water to a rolling boil. Add fettuccine and cook until al dente. Before draining, reserve at least 1 cup of the starchy pasta water.
- Reduce the heat under the skillet to low. Add the butter and let it melt gently. Add the minced garlic and sauté for about 60 seconds until fragrant—do not let it brown!
- Pour in the heavy cream and chicken broth. Bring to a very gentle simmer (barely bubbling) and cook for 3 minutes, allowing it to reduce slightly.
- Remove the skillet completely from the heat. Gradually whisk in the grated Parmesan cheese, a handful at a time, stirring constantly until the sauce is smooth and glossy. Stir in the nutmeg, salt, and white pepper.
- Slice the rested chicken into thick strips. Add the drained fettuccine directly into the sauce pan. Toss to coat. If the sauce seems too thick, add reserved pasta water one tablespoon at a time until the sauce clings perfectly.
- Divide pasta among bowls. Top with the sliced chicken, an extra dusting of fresh Parmesan, and chopped parsley. Serve immediately.