Bring a pot of salted water to a boil. Add the orzo pasta and cook, stirring occasionally, until al dente, about 5-8 minutes. Reserve 2 tablespoons of pasta cooking water, then drain.
In a skillet over medium heat, melt half the butter. Sauté the garlic and tomatoes for 5 minutes, continuously tossing and stirring to ensure the tomatoes cook on all sides and the garlic doesn’t stick to the bottom.
Remove pan from heat. Stir in the mozzarella and the reserved pasta cooking water. The mozzarella will become gooey while the pasta water will help the tomato juices form a nice sauce to coat the pasta. Add the torn basil, salt, and pepper.
Add the cooked orzo and the remaining butter. Stir until the butter is melted and the pasta is evenly coated, then serve.