Set oven to 420F/216C.
Rub the chicken breasts well with seasonings. Place them on a baking sheet lined with parchment paper or on a baking rack, then bake for 15 to 20 minutes. Tip: for the final 2 minutes of baking, broil the chicken breast to blacken the edges and top of the chicken breast. After baking, allow the breasts to cool, then chop them into pieces.
Cook fettuccine according to the instructions given and reserve some of the pasta water.
Set a (nonstick) skillet on medium heat and add olive oil and garlic. Cook for about 2 minutes and do NOT burn the garlic.
Reduce the heat, then add milk, pumpkin and 1/2 cup parmesan. Mix together until you have a consistent, smooth alfredo sauce. Add the cooked fettuccine and fold everything together. Add tablespoons of pasta water if the sauce is too thick.
Toss in the raw spinach and cook until the spinach has wilted.
Add the chopped chicken breasts, then garnish with parsley and the remaining 2 tablespoons of parmesan. Season to taste with sea salt & pepper.