Heat a large skillet over medium-high heat. Add the sausage and brown, breaking it up as it cooks.
Combine the milk and the flour in a small bowl and whisk until smooth. Add the milk mixture to the skillet and bring to a boil, stirring the whole time. Reduce the heat to a simmer and add the sharp cheddar, Monterey Jack, cream cheese, onion powder, garlic powder and salt. Cook until the cheeses melt, stirring the whole time. Add the pasta and stir to coat.
Garnish with parsley before serving, if desired.
