Preheat the oven to 450°F. In a medium saucepan bring 2 cups water, the broth and the saffron or turmeric, if using, to a boil. Add the orzo and cook for 6 minutes, adding the peas during the final 3 minutes of cooking. Drain, reserving 1/2 cup of the cooking liquid.
Meanwhile, in a very large oven-safe skillet heat the oil over medium heat. Add the onion and cook until tender, 6 to 8 minutes. Add corn and cook 2 minutes more. Stir in the drained orzo mixture, reserved cooking liquid, and the shrimp. Season with salt and pepper. Place the tomatoes on top of the mixture in the skillet and transfer the skillet to the oven.
Bake for 10 to 15 minutes or until the liquid has been absorbed and the tomatoes are soft. Top with the parsley and serve.