Bring a large pot of salted water to a boil and cook the penne according to package instructions until al dente, then drain.
In a large skillet, heat the olive oil over medium-high heat and add the diced onion, cooking until translucent.
Add the ground turkey to the skillet, breaking it up with a spoon as it browns, and season with salt, pepper, Italian seasoning, and red chili flakes.
Once the turkey is fully cooked, stir in the minced garlic and cook for 1 minute until fragrant.
Sprinkle the flour over the turkey mixture and stir constantly for 1 minute to coat.
Slowly pour in the chicken broth and tomato sauce while stirring to create a smooth base, bringing to a simmer.
Lower the heat, stir in the half-and-half, and gradually fold in the mozzarella and cheddar cheeses until the sauce is melted and creamy.
Add the cooked pasta into the skillet, toss to coat thoroughly in the cheese sauce, garnish with fresh parsley, and serve immediately.