Bring a large pot of salted water to a boil. Add the fettuccine pasta and cook according to package instructions until al dente, usually about 8-10 minutes. Stir occasionally to prevent sticking.

Once cooked, reserve ½ cup of pasta water, then drain the pasta in a colander and set aside.

In a skillet, heat the olive oil over medium-high heat. Season the chicken pieces with salt and black pepper.

Add the chicken to the skillet and cook for about 5-7 minutes, stirring occasionally, until the chicken is golden brown and cooked through. Use a meat thermometer to ensure it reaches an internal temperature of 165°F (75°C).

Remove the chicken from the skillet and set aside.

In the same skillet, add minced garlic and sauté for about 1 minute until fragrant, being careful not to burn it.

Pour in the heavy cream and chicken broth, stirring to combine. Bring to a gentle simmer.

Add the grated Asiago cheese and dried Italian herbs, stirring until the cheese is melted and the sauce is smooth.

If the sauce is too thick, add reserved pasta water a little at a time until desired consistency is reached.

Stir in the cooked chicken and chopped spinach, cooking for an additional 2-3 minutes until the spinach is wilted.

Add the drained pasta to the skillet and toss to coat the pasta evenly with the sauce. Cook for another 1-2 minutes to heat through.

Serve hot, garnished with chopped parsley and additional grated Asiago cheese if desired.