In a large skillet, stir together 2 cups chicken broth, 2 cups milk or cream, butter, salt and pepper. Bring to a low simmer over medium heat.
Stir in macaroni. Cover and cook, stirring every 4-5 minutes until al dente (about 10-12 minutes total), adding more liquid gradually if needed.
Stir in cheese until melted -- if necessary, cover and let rest a few minutes off the heat to melt the cheese and then stir. If sauce is took thick, gradually stir in additional broth or milk until it comes together.
*If you don't have gruyere cheese, feel free to substitute with additional cheddar cheese or another cheese you have on hand.