Heat oil in a large, high-sided skillet over medium-high heat. Add onion and garlic; cook, stirring often, until the onion is slightly softened and the garlic is fragrant, 2 to 3 minutes. Add broth and bring to a boil over medium-high heat. Stir in orzo, salt and pepper. Reduce heat to medium; simmer, uncovered, stirring occasionally, until the broth is almost absorbed and the orzo is al dente, about 10 minutes. Add cream cheese and stir until melted. Add spinach, basil and Parmesan; cook, stirring constantly, until the spinach is wilted and the Parmesan is melted, about 2 minutes. Let stand for 5 minutes. Garnish with additional basil and/or Parmesan, if desired.