Cook the Pasta: Bring a large pot of salted water to a boil. Add the penne pasta and cook according to package instructions until al dente, usually about 9-11 minutes. Drain the pasta and set it aside, reserving a little pasta water if needed.

Sauté the Chicken: In a large skillet, heat 2 tablespoons of olive oil over medium heat. Add the diced chicken breasts and cook for 5-7 minutes until golden brown and cooked through. Remove chicken and set aside.

Cook the Aromatics: In the same skillet, add chopped onion and minced garlic, sautéing for about 2-3 minutes until translucent and fragrant.

Add the Vegetables: Stir in mixed vegetables and cook for an additional 5 minutes, keeping them crunchy.

Thicken the Sauce: Sprinkle all-purpose flour over the veggies, stirring well. Cook for about 1 minute.

Whisk in the Broth: Gradually pour in chicken broth while whisking to avoid lumps until thickened, about 3-5 minutes.

Add Cream and Seasoning: Reduce heat and stir in heavy cream, thyme, salt, and pepper. Simmer for 5 minutes.

Combine Everything: Add the cooked chicken and drained pasta to the skillet, mixing well to coat.

Finish with Cheese and Herbs: Stir in Parmesan cheese and parsley until the cheese melts into the sauce.