In a large skillet with a tight-fitting lid, heat the EVOO, two turns of the pan, over medium heat. Add the onion and cook until softened, about 2 minutes. Stir in the garlic and season with salt and pepper. Stir in the orzo, increase the heat to medium-high and cook until slightly browned, 3-5 minutes. Stir in the rice, turmeric and saffron. Add the wine and cook for 30 seconds, then add the stock and cover. Bring to a boil, then lower the heat and simmer until the rice is al dente, 7-8 minutes.
Stir in the mussels, peas and tomatoes and cover and cook until all the mussels have opened, 8-10 minutes (discard any unopened mussels). Serve the pilaf in shallow bowls and top with the parsley.