Heat the olive oil in a large deep skillet over medium-high heat. Add the ground turkey, season with 1/2 teaspoon salt and the black pepper, and cook, breaking it into crumbles, until no pink remains, about 5 minutes. It must reach 165°F internally — it will get there well before the end of the recipe.

Stir in the onion and cook until softened, about 2 minutes. Add the garlic, red pepper flakes, and Italian seasoning; cook 1 minute more, until fragrant.

Pour in the chicken broth and milk, scraping up any browned bits from the bottom of the pan. Stir in the penne and the remaining 1/4 teaspoon salt. Bring to a lively simmer.

Reduce the heat to medium-low, cover, and cook, stirring once or twice, until the penne is just tender and most of the liquid is absorbed into a thin, brothy sauce, about 9 minutes. The pasta cooks directly in the skillet — no boiling, no draining.

Uncover and drop in the cream cheese cubes, stirring until melted and smooth. Take the pan off the heat and stir in the Greek yogurt, Parmesan, and nutmeg until the sauce turns silky. (Off the heat is the key — it keeps the yogurt from curdling.)

Fold in the spinach a handful at a time; it wilts into the hot pasta in about a minute. Shower with parsley and extra Parmesan and serve right away.