In a medium pot, heat the olive oil and butter over medium heat. Add the garlic and cook for 1 minute. Make sure you frequently stir to prevent the garlic from burning.
Add the chicken broth to the pot.
Increase the heat to medium-high and let it come to a boil.
Add the pasta and cook till tender (about 4 minutes).
Take the pot from the heat and add the parmesan. Stir until the cheese has completely melted. Add salt and pepper.
Add the milk and green onion. Stir
The pasta will thicken as it cools so allow it to sit for a minute or two before serving. Season with additional salt and pepper is needed.