In a large skillet, heat the olive oil over medium heat. Add the diced onion and sauté for about 3-4 minutes until translucent.
Stir in the minced garlic and cook for an additional 1 minute until fragrant.
Add the shrimp to the skillet and season with salt, pepper, and Italian seasoning. Cook for about 2-3 minutes until the shrimp turn pink.
Stir in the orzo, cherry tomatoes, and vegetable broth. Bring the mixture to a boil, then reduce the heat to low. Cover and simmer for about 10-12 minutes, stirring occasionally, until the orzo is cooked and has absorbed most of the liquid.
Once the orzo is cooked, stir in the baby spinach and grated Parmesan cheese. Cook for an additional 2 minutes until the spinach wilts.
Remove from heat and let it sit for a few minutes before serving. Garnish with fresh basil if desired.