Stir the flour, garlic powder and black pepper in a 4-quart saucepan. Add the broth to the saucepan and stir until the mixture is smooth. Cook and stir over medium heat until the mixture boils and thickens. Remove the saucepan from the heat.
Stir the yogurt in the saucepan. Add the pasta and 4 tablespoons of the cheese and toss to coat. Sprinkle the pasta mixture with the parsley and remaining cheese.