Melt the butter in a medium skillet over medium-low heat. Add the pasta and onion; cook until the pasta is golden brown and the onion has softened. Add the garlic and cook until fragrant (1 minute). Mix in the rice and chicken broth, turn heat to high and bring to a boil. Reduce heat to medium-low, cover and simmer for 20 to 25 minutes (until the liquid is absorbed and the rice is tender).
Remove from heat, stir, and add salt and pepper to taste. Stir in parsley, if using.