Pat chicken thighs dry and bring to room temperature. Season generously on all sides with garlic powder, paprika, dried basil, Italian seasoning, salt, and pepper.

Heat olive oil in a large Dutch oven or heavy-bottomed pot over medium-high heat until sizzling.

Brown chicken in batches on both sides. Lower heat slightly and continue cooking until fully cooked through, about 10–15 minutes total.

Transfer chicken to a bowl and set aside. Do not discard the juices — they go back into the sauce.

In the same pot, add onion and garlic with a pinch of salt and pepper. Sauté until soft, translucent, and lightly golden.

Add tomato paste and cook, stirring, until deepened in color and slightly caramelized, about 2–3 minutes.

Pour in wine and scrape up all the flavorful bits from the bottom of the pot. Simmer until alcohol cooks off.

Add crushed tomatoes, season again with salt and pepper, and simmer for about 5 minutes.

Rinse the tomato can with some chicken stock and add it to the pot along with the remaining stock.

Stir in heavy cream. Cover and bring to a rolling boil, seasoning again as needed.

Salt the liquid generously (like pasta water). Add dry pasta, cover, and bring back to a boil.

Uncover and cook at a steady boil, stirring often, until pasta is al dente and the sauce thickens, about 12–14 minutes.

Slice half the chicken on a diagonal and return it to the pot with all reserved juices.

Lower heat to very low. Stir in most of the cheese and the spinach until melted and wilted.

Taste and adjust seasoning. Serve topped with remaining sliced chicken, extra cheese, and parsley if desired.