Begin by filling a large pot with water and adding a generous pinch of salt. Bring to a rolling boil, then add the penne pasta. Cook for 8-10 minutes until al dente, reserving a cup of pasta water before draining.

In a large skillet, heat olive oil over medium heat until shimmering. Add diced yellow onion and sauté for approximately 5 minutes until soft and translucent.

Add the ground turkey, breaking it apart with a wooden spoon. Cook for 6-8 minutes until browned and cooked through. Season with salt, pepper, and Italian seasoning. Add minced garlic and cook for one additional minute until fragrant.

Sprinkle all-purpose flour over the turkey mixture and stir for about 1 minute. Gradually pour in chicken broth and tomato sauce, stirring until smooth. Bring to a gentle simmer for 3-5 minutes, allowing to thicken.

Fold the cooked penne pasta into the turkey sauce mixture, incorporating half-and-half and adding reserved pasta water as needed for desired consistency.

Lower the heat and sprinkle half of the mozzarella and cheddar cheese over the pasta. Stir until melted. Top with remaining cheese and cover to rest off heat for a few minutes.

Garnish with chopped parsley and red chili flakes, then serve warm in bowls.