Bring a large pot of salted water to a boil and add the orzo. Cook according to package directions until al dente. Drain.
Once pasta is cooked, set aside to allow the pasta to cool. Add the remaining ingredients and stir to combine. Garnish with basil leaves. Refrigerate until ready to serve.
In the bowl of a food processor or blender, combine the basil leaves, garlic, pine nuts, and 1/2 cup of the olive oil. Pulse until well chopped and blended. Add the cheese and pulse to combine. Pour into a small bowl and cover with the remaining olive oil.