Melt butter in a heavy skillet over medium-high heat. Saute onion until soft. Stir in garlic and orzo and sauté until lightly browned.
Stir in chicken broth and bring to boil. Cover, reduce heat, and simmer until orzo is tender and liquid is absorbed, 15 to 20 minutes.
Mix in Parmesan cheese and ¼ cup chopped basil. Season with salt and pepper. Transfer to a shallow bowl and garnish with remaining basil.
