Bring a large pot of salted water to a boil, add whole wheat pasta, and cook until al dente, about 8-10 minutes. Reserve 1/4 cup of pasta water before draining.

In a large skillet, heat olive oil over medium heat, add cubed chicken breast seasoned with salt, pepper, paprika, and Italian seasoning. Sauté until golden and cooked through, about 5-6 minutes.

In the same skillet, add minced garlic and sauté for 30-60 seconds until fragrant.

Sprinkle whole wheat flour into the skillet, stirring continuously for about 30 seconds to form a roux. Gradually whisk in chicken broth and low-fat milk, cooking until the sauce thickens.

Lower the heat, add Greek yogurt, stirring until smooth, then add grated Parmesan cheese and mix until melted. If too thick, add a splash of reserved pasta water.

Return cooked chicken and juices to the skillet, add drained pasta and spinach if using, tossing everything together until well coated.

Serve immediately, garnished with parsley and additional Parmesan cheese if desired.