Boil the Pasta: Bring a large pot of salted water to a boil. Add the Acini de Pepe and cook according to package instructions until al dente (about 7 minutes). Stir occasionally to prevent sticking.
Drain the Pasta: Once cooked, drain the pasta and return it to the pot.
Add Butter: Add the butter to the hot pasta and stir until completely melted and the pasta is evenly coated.
Add Parmesan: Sprinkle the grated Parmesan cheese over the pasta and stir well. Add salt and pepper to taste.
Serve: Transfer the pasta to serving bowls. Garnish with fresh chopped parsley if desired.